Consumer Information

A Gardener’s Guide to Planting by Hardiness Zones

Posted on May 3, 2025May 20, 2025 by Zidack, Heather

By Marie Woodward, UConn Home & Garden Education Center

Map of Connecticut USDA Hardiness zones as of 2023. Most zones in the state are either zone 6 or zone 7. — USDA Hardiness Zone Map for Connecticut, 2023

If you are wondering whether that shrub, flower, or tree that you saw in a magazine or catalog will grow well in your garden, using a hardiness zone map is your best bet to ensure success.

A hardiness zone map is a tool that divides a geographical area into distinct zones based on average annual minimum winter temperatures. These maps are used by gardeners and farmers around the world to determine which plants are most likely to thrive in a particular region. Each country has its own hardiness map that correlates to their climate. In the United States, the USDA publishes a hardiness zone map, which covers all fifty states and includes Puerto Rico, Guam, American Samoa, and the U.S. Virgin Islands. It uses climate data collected over many years from weather stations throughout a specific region. Then the data is analyzed to determine average minimum winter temperatures from different areas.

The concept of hardiness zones was first introduced in 1927 by Dr. Alfred Rehder. Rehder worked at Harvard's Arnold Arboretum as a botanical taxonomist. He wanted to address the challenges gardeners and growers faced in selecting plants suited to their local climate. Prior to Rehder’s map, there was no standardized system for categorizing plants based on their ability to survive winter temperatures. His hand-drawn map featured eight hardiness zones and was based on the lowest winter temperatures recorded in various regions across the country. Rehder aimed to provide a practical tool for gardeners and growers. His map made it easier for them to choose plants with the best chances of survival in their region, ultimately contributing to more successful gardens and agricultural endeavors. Rehder’s innovative approach recognized the importance of adapting agricultural practices to local climates. In the 1960s, the USDA adopted and adapted Rehder's concept, creating the first official USDA Plant Hardiness Zone Map.

Since its initial release, the USDA Plant Hardiness Zone Map has been updated several times to reflect changes in climate and the availability of more accurate data. The latest update of the USDA hardiness map was released in November 2023, jointly developed by the USDA's Agricultural Research Service (ARS) and Oregon State University's PRISM Climate Group. This update incorporates data from 1991 to 2020, covering a broader range of weather stations than previous versions. One of the key findings from this update is that the contiguous United States has become approximately 2.5 degrees Fahrenheit warmer on average compared to the previous map. As a result, around half of the country has shifted into the next warmer half zone, while the other half has remained unchanged. The updated map still consists of 13 zones, but now offers more detailed information on temperature ranges within each zone, including 10-degree zones and 5-degree half zones. Connecticut has two hardiness zones each of which is divided into half zones; (6a,6b); (7a,7b), to better reflect the temperatures in the state over the past few decades.

The importance of hardiness zones lies in their ability to help gardeners and farmers choose plants that will thrive in their specific region. By selecting plants appropriate for their zone, growers can reduce the risk of frost damage and increase their chances of a successful growing season. However, due to unexpected temperatures outside the average range, there is no guarantee that a plant won’t suffer but it does reduce the risk of plant damage. In addition to gardeners, researchers use hardiness zones to study the spread of insects and exotic weeds, while the USDA Risk Management Agency uses the map to help determine crop insurance rates for commercial growers.

While the USDA Plant Hardiness Zone Map is an invaluable tool, it is important to note that it is not the only factor gardeners and farmers should consider when selecting plants. Other factors, such as soil type, precipitation, and local microclimates, can also impact plant growth and survival. Gardeners should use the map as a starting point and supplement it with local knowledge and research to make the best plant selections for their specific needs.

The development of the USDA Plant Hardiness Zone Map is a testament to the importance of adapting agricultural practices to local climates. Since its inception nearly a century ago, the map has evolved to reflect changes in climate and incorporate more accurate data. Today, the map remains an essential resource for gardeners and researchers alike, helping them to better understand and navigate the complexities of plant growth in the diverse regions of the United States. Knowing a plant’s hardiness zone when selecting that shrub, tree or flower will help you grow the garden of your dreams.

The UConn Home & Garden Education Center supports UConn Extension’s mission by providing answers you can trust with research-based information and resources. For gardening questions, contact us toll-free at (877) 486-6271, visit our website at homegarden.cahnr.uconn.edu, or reach out to your local UConn Extension center at cahnr.uconn.edu/extension/locations.

Celebrate Arbor Day!

Posted on April 26, 2025May 20, 2025 by Zidack, Heather

By Dawn Pettinelli, UConn Home & Garden Education Center

Redbud tree in flower with tiny pink buds. — Photo by Dawn Pettinelli

Arbor Day is celebrated in Connecticut on April 25th. Since it is a day traditionally set aside for the planting of trees, perhaps you might consider adding one to your home landscape. If you haven’t the need for another arboreal specimen, then plan on giving your existing trees a little TLC.

Trees have a lot to offer. They provide us with cool shade on hot summer days, brighten our spring season with lovely blossoms, add color to the fall landscape and winter interest throughout cold, dreary days. Trees provide food, nesting sites and shelter for many animals, especially birds. They help reduce noise pollution, trap particulate air pollutants, and can alter the microclimate surrounding them.

Most importantly, trees supply plenty of oxygen for us to breathe. Each year, an acre of trees produces enough oxygen to keep 18 people alive. They also sequester carbon dioxide. Trees convert atmospheric carbon dioxide into plant matter as they photosynthesize. This has important consequences worldwide. As more and more of our forested land is being cleared, less carbon dioxide can be stored in trees and more is available to increase the atmospheric carbon dioxide levels which, in turn, can contribute to global warming.

While we can’t stop global deforestation, we can make a difference in our own backyards by planting more trees or making sure that the trees already present receive the conditions they need to thrive.

When selecting a tree for your landscape, do consider factors like its ultimate height and spread, susceptibility to insect and disease problems, flowering, fruiting and fall foliage potential, rate of growth and site requirements. Review gardening books, consult with nurserymen and maybe visit an arboretum to view mature specimens.

Trees are purchased either as dormant stock through mail order sources, containerized, or balled-and-burlapped (B & B). Dormant trees generally arrive in the spring or fall and should be soaked for a couple of hours and planted immediately. If you can’t get them in the ground right away, they can be stored in a cool place for a few days out of direct sunlight. Make sure them are kept moist.

Containerized stock can be planted throughout the growing season although cooler spring or fall is best. Hard to transplant species are best purchased this way as there is less disruption to their root system. If potbound, make several vertical cuts about one-quarter inch deep around the root ball before planting.

Purchasing B & B trees is fine for younger specimens, but often larger trees have a good portion of their roots removed in this process. This can lead to poor survival. For greatest success, choose small to medium sized trees.

A tree planted at the proper depth with the crown slightly exposed. The hole is dug twice the width as the original root ball. — Photo by Dawn Pettinelli

Holes for planting only need be as deep as the root system. The key is to make them at least 2 feet wider than the root ball. Especially in heavy or compacted soils, be sure to

loosen as much soil around the planting area as possible so roots can grow freely. The majority of roots are found in the upper 3 feet of soil.

Amendments such as peat moss or fertilizer are not necessary to add to the backfill. However, if the soil pH or phosphorus levels are low, ground limestone and bonemeal can be mixed into the backfill.

Add water to the hole before planting and let it drain. Next, position the root ball. Remove plastic mesh and cords. Burlap can be cut away as much as possible. Fill in the hole about half way. Gently firm the soil around the root ball. Don’t stomp on it or you will compact the soil. Water thoroughly and when the water drains, finish filling the hole. Make a well around the tree with soil and water once more. Apply a 2 to 3 inch layer of mulch keeping it away from the trunk. Newly planted trees need a thorough soaking each week throughout the first growing season either from natural precipitation or from you.

If you have questions about trees or any other gardening topic, call the UCONN Home & Garden Education Center (toll-free) at (877) 486-6271 or email us at ladybug@uconn.edu or visit our website, www.homegarden.cahnr.uconn.edu.

Garden centers prepare for nice weather as spring fever spreads

Posted on March 19, 2025March 20, 2025 by Zidack, Heather

Have You Tested Your Well Lately?

Posted on March 15, 2025March 18, 2025 by Zidack, Heather

By Alec Janis M.S. – Connecticut Institute of Water Resources

Cross-section of how water moves underground. Photo created by Alec Janis, M.S.

In 1718, in what is now Franklin, Connecticut, a well was dug as an all-purpose public source of water for the community. In about 1755, the people began to complain about the water’s quality, saying it stained clothes and remained tainted until 1794, when an earthquake shook the town. After the earthquake, it was found that the well had been restored to its original quality. Although this is a more extreme example, the quality of your well water can change at any time, which means that just because it was safe to drink when it was installed, that may not be the case today.

The Connecticut Department of Public Health recommends that all residents test their wells every two to five years. If you’re struggling to remember the last time you tested your well, you’re not alone. We estimate that 96% of Connecticut well owners do not follow these guidelines.

So how does your well work? When it rains, some water is absorbed by the plants in the landscape, but they can’t uptake all that water. After water travels past the plant roots, it continues until it reaches an area where all the spaces in the soil have been saturated. This is known as the water table. Think of the soil like a sponge; as you add water, the water fills all the holes and space inside until it’s completely soaked through. If you have a shallow well, your water is being pulled directly from this water table.

If you have a drilled well, your water comes from much further underground. Below the saturated layer of soil, there’s solid stone called bedrock. Throughout the bedrock, there are small cracks, called fractures, where water moves. You can see an example of this when passing a rocky cliff face along the highway that seems to be randomly covered in ice. The ice you see has formed from water that has made its way through soil on top of the ledge, into the fractures in the stone and eventually drips out of small cracks where it freezes in the cold air. A drilled well is a bored hole in the bedrock, intersecting many fractures. Instead of following the original path, water now pours out of the fractures and pools in the newly formed hole.

Now that we know how water travels, let’s consider everything the water is interacting with on its way down. Consider the animal waste on your lawn from a pet or a passing deer, the fertilizers or pesticides you may use on your lawn, or even the de-icing salts you put on walkways during the winter. Precipitation, in the form of rain or snow, pulls everything underground. However, not all of this will end up directly in your well water. The dirt acts as a filter stopping some contaminants while letting others through. Depending on the chemical make-up, certain compounds will remain in the soil while others will break down and continue to travel through.

When this water reaches the bedrock, it will continue to pick up and lose different chemicals. This process will slowly erode these cracks, causing the paths to change over time. As the stone erodes, metals and minerals will be picked up with the traveling water and occasionally end up in your drilled well.

This is why it is important to routinely test your well water quality every few years. As water erodes fractures in the bedrock, new cracks and pathways form, changing the contaminants that are entering your well. We currently don’t have a simple method to track how groundwater is moving, so testing is the best way to understand what’s happening in your well.

To get your well tested visit a local or lab participate in the UConn Extension well testing program. We are hosting a collection event at the UConn Extension - Middlesex County Extension Center (1066 Saybrook Rd, Haddam, CT 06438) on May 3^rd from 10:00am – 1:00pm. These tests test for coliform bacteria, lead, arsenic, uranium, nitrates, sodium, chloride, fluoride, pH, hardness, sulfate, turbidity, iron, and manganese. These tests, normally valued at $350, are being offered for a reduced cost of $200.

We will mail a sample kit to participants who have signed up in advance of the collection event. Sample kits will also be available at the collection event on May 3^rd as well as at the Old Saybrook Environmental Fair (Old Saybrook Middle School, 60 Sheffield St, Old Saybrook, CT 06475) on April 26^th.

Participants can sign up online at https://s.uconn.edu/haddam-well-testing. The deadline to be mailed a sample kit is April 25th.

If participants cannot make the day above, we offer a walk in service year-round where participants can bring their water sample to the UConn main campus Monday through Thursday from 8 am – 5 pm. For more information on how to sign up, visit https://ctiwr.uconn.edu/walk-in/.

We support UConn Extension’s mission by providing answers you can trust with research-based information and resources. For home gardening questions, contact the UConn Home & Garden Education Center at homegarden.cahnr.uconn.edu, or reach out to your local UConn Extension center at cahnr.uconn.edu/extension/locations. For more information about the CT Institute of Water Resources and Well testing services, visit https://ctiwr.uconn.edu/

The Challenges of Boxwood: Pests, Diseases, and Alternatives

Posted on February 22, 2025February 27, 2025 by Zidack, Heather

By Marie Woodward, UConn Home & Garden Education Center

Boxwood, a classic choice for formal gardens and hedges, has faced increasing threats in recent years. As gardeners grapple with these challenges, it is crucial to understand the issues at hand and explore alternative plants for our landscapes.

Boxwood Blight is an aggressive fungal disease that affects various Boxwood species and causes rapid defoliation and potential plant death. First identified in the United Kingdom in the mid-1990s, this disease has since spread across North America. Early symptoms include stem cankers, sunken lesions, and eventual dieback. To mitigate the risk of Boxwood Blight, choose resistant cultivars, practice good garden hygiene, and monitor your plants for early signs of infection.

The Box Tree Moth is an invasive pest native to Asia that feeds on Boxwood plants. Since its arrival in North America, this moth has wreaked havoc on Boxwood populations, leading to defoliation and plant stress. Symptoms of infestation include see-through plants, "stick shrubs," and stem cankers. Regular monitoring and integrated pest management strategies are essential for controlling this destructive insect.

As Boxwood plants continue to face challenges from pests and diseases, it is wise to consider alternative options for our gardens. Ilex crenata (Japanese Holly) is a versatile, broadleaf evergreen that can be shaped into hedges or topiaries. Its small, glossy leaves provide a neat appearance, and its adaptability to various soil types and sun exposure makes it a low-maintenance choice.

Row of Gem Box Ilex shrubs for sale — Gem Box Ilex is one of many fantastic substitutes for Boxwood shrubs. Photo by H. Zidack

Euonymus japonicus (Japanese Euonymus), an evergreen shrub with small, glossy leaves and tolerance for a range of growing conditions is another possible substitution. Its compact growth habit and easy maintenance make it an excellent choice for hedges or screens.

Ilex glabra (Inkberry), is a slow-growing evergreen native to North America, featuring dark green leaves and red berries in the fall. Its low, spreading habit makes it ideal for low hedges or mass plantings.

Privets (Ligustrum), are fast-growing, low-maintenance evergreen shrubs with small, glossy leaves. They can be used for hedges, screens, or as stand-alone specimens. However, keep in mind that three cultivars, border privet, (Ligustrum obtusifolium Sieb. & Zucc), California privet, (Ligustrum ovalifolium Hassk.) and European privet (Ligustrum vulgare L.) are listed on UConn’s invasive plant database. If you decide to plant privets, look for seedless cultivars such as Golden Ticket privet (Ligustrum x vicaryi "KCLX1") at your local nursery.

The Boxwood Blight and Box Tree Moth present ongoing challenges for gardeners and landscapers. By understanding these threats and adopting appropriate management strategies, we can mitigate the damage they cause. Additionally, exploring alternative plants can help create more resilient and sustainable gardens in the face of these challenges. With careful planning and thoughtful plant selection, our landscapes can continue to thrive in the face of adversity.

The UConn Home & Garden Education Center supports UConn Extension’s mission by providing answers you can trust with research-based information and resources. For questions about your boxwoods or other gardening questions, contact us toll-free at (877) 486-6271, visit our website at homegarden.cahnr.uconn.edu, or reach out to your local UConn Extension center at cahnr.uconn.edu/extension/locations.

Shine a Light – But Which One?

Posted on February 15, 2025February 18, 2025 by Zidack, Heather

By Emily Leahy, UConn Home & Garden Education Center

Seedlings under LED lights — Seedlings growing under programmable LED lights. Photo by H. Zidack

The dead of winter brings a longing to spend time outside in the garden again. While this may not be possible yet, it is easy to craft your own growing space indoors. The elements of the outdoors that allow plants to thrive – light, warmth, and water – can all be brought indoors with a little creativity and the right resources.

Some steps remain unchanged. Still, refer to the plant’s label for guidance on choosing a proper container, water and nutrient needs, as well as temperature preferences. Guidelines on how much light the plant should receive can also be found on the label – but how can this be applied indoors?

One of the more challenging aspects to simulate, indoors, is an adequate amount of light. When outside, plants rely on the sun for light needed to carry out photosynthesis. This chemical reaction produces sugars which are used as energy in processes essential for the growth and maintenance of a healthy plant. While plants can still receive sunlight indoors through rays shining through windows, this often cannot act as an equitable substitute for unobstructed sunlight outdoors. This is where supplemental light sources in the form of grow lights come into play. Grow lights are specially designed with the purpose of emitting a wider spectrum of light wavelengths to enable photosynthesis. But with so many options available, how can you choose which is the best option?

Generally, there are two types of grow lights – bulbs and fixtures. Bulbs can be placed into existing light fixtures like lamps or overhead lighting. However, this can be unsuitable as it is difficult to control the distance from the plant and angle at which the light shines. Grow light fixtures are separate systems which can provide multiple plants with light simultaneously, offering a more even distribution. With proper setup, they can be positioned at an advantageous angle to provide plants with their preferred amount of light.

Next comes the question of which kind of light is appropriate for your plant – incandescent, fluorescent, or LED? It is important to determine beforehand the level of light which your plant prefers – high, medium, or low. Incandescent lights, while costing the least, are also the least efficient. 90% of their energy is released in the form of heat, while only 10% is light itself. While this makes them good contenders for low-light plants, they also require caution as they can provide plants with an overwhelming amount of heat.

Fluorescent lights are well-suited for plants requiring low to medium light. They emit the full spectrum of light, essential for promoting growth as they mimic natural sunlight. Most often they are seen as strips or tubes of light that can be affixed above plants, but they can also be purchased in bulb form. LED lights emit the full spectrum of light as well, while simultaneously emitting less heat than other bulb types. Yielding a high overall efficiency, LEDs can be customized with different colors/wavelengths of light to provide certain advantages for some plants. For example, blue lights promote vegetative growth, while red lights do the same for flowering and fruit growth.

Grow light setup — Different stages of growth may need different spectrums of light. Photo by H. Zidack

After choosing the most suitable kind of grow light for your plant, there are a variety of other tips helpful to consider. The type of plant not only determines the proper type of light to use, but also how much light should be provided. Supplying light 24 hours a day is not ideal as it can overwhelm the plant – remember the objective is to mimic the light conditions of the outdoors. Therefore, plants will require some hours of darkness each day.

Seedlings generally prefer 14-16 hours of light per day, as they necessitate the most encouragement for growth. 12 hours of light is suitable for herbs and other greens, while houseplants fall between the range of 6-12 hours per day – be sure to refer to the product label for any specifications on light preferences.

In terms of setup, lights should be angled to ensure a direct stream of emittance onto the plant in order to receive its full benefits. It is best to affix lights about 12 inches from the plant, although adjustments can be made as you see fit. Some indoor gardening systems are available that can be customized to fit specifications according to the type of plant being grown. It is also important to purchase lights that are rated to withstand humidity and moisture if they are being kept in a greenhouse-like environment.

Be sure to always refer to your plant’s label for its specific preferences for light and other growing conditions. With the help of grow lights, you can wait out the winter by bringing a little bit of the outdoors, indoors!

The UConn Home & Garden Education Center contributes to the Cooperative Extension mission of the University of Connecticut by connecting the public with research and resources provided by the University. For your gardening questions, feel free to contact us, toll-free, at the UConn Home & Garden Education Center - (877) 486-6271, visit our website at https://homegarden.cahnr.uconn.edu/, or contact your local Cooperative Extension center https://cahnr.uconn.edu/extension/locations/.

All-America Selection Winners for 2025

Posted on January 19, 2025February 4, 2025 by Zidack, Heather

by Dawn Pettinelli, UConn Home & Garden Education Center

Each winter the All-America Selection winners are announced. This non-profit organization has established trial gardens throughout the United States and even as far north as Canada. New varieties, species or strains of annuals, vegetables and bedding plants are grown and judged on their performance. Those chosen as winners are outstanding plants and deserve a trial in your gardens as well.

This year’s national winners include 3 vegetables and 5 flowers. ‘Green Lightening’ is a very attractive, striped pattypan squash that tastes as good as it looks. The 5-inch or so fruits weigh in at 1 to 2 pounds and are ready to pick about 50 days after planting from seed. Judges marveled at the abundant yields on these 2 feet high, bushy plants.

Kohlrabi ‘Konstance’ Image by all-americaselections.org

Kohlrabi ‘Konstance’ exudes a vibrant purple color as well as a sweet, crunchy texture. A curious but easy to grow and tasty addition to the vegetable garden, this kohlrabi matures at just 42 days from seed. Upright plants, about a foot high, produce round, purple 4 to 5-inch ‘bulbs’ that can be eaten fresh or served roasted or sauteed. Fruits are crack-resistant and plants resistant to several diseases.

Sweet pepper ‘Pick-N-Pop Yellow’ produces adorable, snack-size, extra sweet mini peppers. The pointed, conical fruits are about 4 inches long springing from compact 2-foot-tall plants. The prolific harvest begins about 65 days after transplanting. This variety shows great resistance to bacterial leaf spot.

One can never have too many dahlias and this year’s AAS winner, ‘Black Forest Ruby’ is a gem that can be started from seed. Since this variety is an octoploid (having 8 times the normal chromosome number) there is much variability in flower shape (ranging from single to double), plant height and structure. Most will be upright about 2 feet high with jet black foliage and ruby-red flowers. You can save tubers from the best-looking plants.

Dianthus ‘Interspecific Capitan™ Magnifica’ with its impressive bicolor pink and white frilly blooms looks as good in the garden as it does in a vase. Plus, the more you cut, the more blooms appear. Summer heat tolerance was impressive with the 2-inch flower heads also standing up to rain and cold. Plants range from 1 to 1 ½ feet tall and bloom all summer. Look for these vegetatively propagated plants at your local garden center.

Sunny sites will positively shimmy when planted with marigold Mango Tango. This rich red and primrose yellow bicolor blooms all summer long even without deadheading. Reaching only 8 to 10 inches in height makes it perfect for edging garden beds, containers or window boxes. Seeds can be started indoors and plants set out after the danger of frost has passed. Fertilize and water regularly for bountiful blooms.

Can there be too many petunias? ‘Petunia Shake™ Raspberry’ will convince you that there’s always room for one more. The fantastic flowers are reminiscent of a blended raspberry milkshake swirled with lemon-lime green sorbet. The 5 to 8 inch mounded plants can do front of the border duty, serve as groundcovers or billow over hanging baskets. Plants will bloom about 70 days from seed and hold up to heat and rain.

Snapdragon‘DoubleShot™ Yellow Red Heart’Image by all-americaselections.org

I’ve never thought of snapdragons as fragrant, yet ‘DoubleShot™ Yellow Red Heart’ is said to have an amazing candy-like scent. Aside from this unusual trait, Yellow Red Heart promises to delight with vibrant yellow blossoms with a red throat that start early and continue through to a heavy frost. This snapdragon reaches about 20 inches in height with semi-double 1 to 1 ½ inch blooms produces all season long and able to tolerate light frosts.

Four regional 2025 Ornamental Winners well suited to the Northeast, include one petunia and 3 nasturtiums. If you’re looking for a vibrant pink petunia great for bedding and containers, try ‘Dekko™ Maxx™ Pink’. The vibrant pink 1 to 1 ½ inch starry blooms are produced all season long and hold up well to rain and heat.

Nasturtiums are top performers in garden beds and containers and are noted for their hummingbird attraction and edible leaves and flowers. New colors in the Baby series of nasturtiums to try out this year might be ‘Baby Gold’, ‘Baby Red’ and ‘Baby Yellow’. All can be grown from seed and start blooming about 50 days after sowing. Two-inch blooms cover compact 12-inch-high mounded plants. Colors are intense and plants stand up to drought, heat, cold, rain and wind. Considering our fluctuating summer weather, these are sure to do well both in the garden and in containers.

Check out these and past AAS winners. They were chosen because of their remarkable characteristics and they are sure to be winners in your yard too.

For your gardening questions, feel free to contact us, toll-free, at the UConn Home & Garden Education Center at (877) 486-6271, visit our website at www.homegarden.cahnr.uconn.edu or contact your local Cooperative Extension center.

Heirloom vs Hybrid – An Age-Old Garden Debate

Posted on January 11, 2025February 4, 2025 by Zidack, Heather

By Heather Zidack, UConn Home & Garden Education Center

Seed catalogs piled on a desk — Seed catalogs can be overwhelming, but many have keys to help identify various traits among their products. Photo by Heather Zidack

Temperatures are dropping, the holidays are over, and gardeners are starting to look towards the next growing season with excitement. Many gardeners swear by the tried-and-true heirloom varieties, while others are drawn to the disease resistance or increased vigor of hybrids. The debate over which is “best” can get heated between gardeners. Do you know the differences?

Pollination is a key factor. Successful pollination occurs when pollen meets the sticky central part of a flower, known as the stigma. Fertilized seeds develop in the ovary, which will then form into fruit. Over the span of thousands of years, tasty fruit has proven to be a good way to help with seed dispersal in the environment. And taste, along with many other traits, have helped humans decide what plants to cultivate.

Hybrid seeds, also commonly referred to as “F1” or “F1 hybrids,” have been developed through selective breeding. To create an F1 hybrid, breeders have selected parent plants with desirable traits and pollinated them under controlled conditions. While it sounds easy enough, lineages can be tricky. It can be time consuming for plant breeders and some will spend years of their career trying to achieve a specific outcome.

F1 hybrids are often praised for their environmental resilience and higher yields, among other traits. They may be less reliable for seed savers, though, as the offspring of the F1 hybrids are not guaranteed to come back with the same traits as the original plant from your first season, a term we call “true to seed.”

Hybrid seed should not be confused with GMO or genetically modified seeds. Hybrid seed is a product of breeding and selection and does not undergo the laboratory interventions that are needed for genetic modification. Currently, there is only one GMO product available to home gardeners, known as “The Purple Tomato.” All other GMO seed is only available commercially and farmers using these products must sign agreements that lay out the terms of use for the seed purchased.

You may find the term “open pollinated” in your search for seed. These seeds are created without direct human intervention. They have stable genetics and produce predictable traits in their offspring year after year, since they are naturally pollinated. This is great news for those gardeners who enjoy saving their own seed.

It is best to plant open pollinated varieties of similar species away from each other to avoid random cross-pollination. Alternatively, gardeners cand hand pollinate a few flowers and keep them covered. For this, I recommend mesh party favor bags that allow for the fruit to expand. Allow the fruit to develop and harvest them specifically for their seed.

Heirloom seeds are open pollinated plants that have been passed down usually over generations. Often, there is a local history or cultural significance that comes with them. You can find interesting physical traits and some beneficial resistances from heirloom seeds. Since they are open pollinated, their genetics are more likely to be stable and produce true to seed offspring for seed savers, as well.

At the end of the day, I always advise gardeners to look beyond the title and really assess what is going to meet your needs and make your experience most enjoyable. If you love to tell a story with your garden, and enjoy saving your seeds year after year, an heirloom variety might be the perfect fit! On the other hand, if you bring home a packet of tomato seeds that have been bred for small space gardening, and you plan to buy new seeds every year, then enjoy that tomato to its fullest! There are many gardens out there with a beautiful blend of both.

If you have questions about seed selection, or for other gardening questions, contact the UCONN Home & Garden Education Center, toll-free, at (877) 486-6271, visit their web site at www.homegarden.cahnr.uconn.edu or contact your local Cooperative Extension Center.

Home and Garden Education Center

Consumer Information

A Gardener’s Guide to Planting by Hardiness Zones

USDA Hardiness Zone Map 2023

USDA Hardiness Zone Map 2012

USDA Hardiness Zone Map 1990