Trial Criteria for the GREENHOUSE PERFORMERS
How to Select Varieties for Greenhouse Growing
What Makes a Variety Right for the Greenhouse?
Greenhouses and poly tunnels of every size, style and level of technology are appearing on farms everywhere as growers learn what protected culture can do. Of its many advantages, the ones growers mention most are a longer season, higher yields and quality, and protection from bad weather and diseases such as early and late blight.
Growing under cover has its own challenges, though: limited space, finding the right combination of variety, nutrients, light and water, more hands-on plant care, and a higher risk of diseases that thrive indoors, such as leaf mold. A crop has to perform especially well to earn a spot in a greenhouse or hoophouse.
Breeders and trial staff spend a great deal of effort finding varieties that suit protected growing. Over time the Hensley's team has refined how it picks out the best indoor performers and separates them from varieties better left in the field. Below are some of our findings, what to look for, and the varieties we expect to do well in your greenhouse.
Above & Beyond Flavor — What We Look For
The Hensley's team runs variety trials on trial plots and together with growers and university researchers in many regions.
A single trial cycle can include well over a hundred tomato varieties in high tunnels plus a range of rootstocks, along with dozens of greenhouse peppers and cucumbers and a smaller set of eggplants.
Each trial is scored on a defined set of traits, including appearance, size, shape, flavor, plant habit, yield and plant health, along with any other notable observations.
The team also works with commercial growers who sell these crops, trialing new varieties on their farms. That gives us feedback on both growing and selling from many locations.
What should you look for when trialing varieties for protected culture? Flavor comes first. Beyond that, a variety is a strong candidate for indoor growing if it stands out in one or more of these areas:
- Flavor — Always the top priority.
- Vigor — The ability to keep producing well beyond a normal field season.
- Plant habit — Limited indoor space rewards compact plants that need less pruning and upkeep.
- Disease resistance — Lower airflow and higher humidity under cover encourage certain leaf diseases, and pests such as whiteflies can quickly spread viruses between plants.
- Higher yield — Needed to pay back the cost of the structure.
- Tolerance of lower light — For example, red lettuce that still colors up fully, or day-neutral sunflowers. We also check whether a variety avoids disease or physiological problems that tend to worsen when glazing reduces light.
- Fruit set without pollinators — Bees and butterflies have limited access inside a structure. This matters most for indoor cucumbers, which is why parthenocarpic varieties are usually recommended under cover.
Our Greenhouse Symbol
Breeders and trial staff select for the strongest genetics so greenhouse growers get dependable varieties suited to indoor conditions. When a variety proves itself in trials, it earns the greenhouse symbol. When you see the Greenhouse Performer symbol next to a variety on our site, you know it has been carefully tested and judged worthy of space in your greenhouse.
The result is a lineup of vegetables, herbs, flowers and fruit chosen to make the most of valuable covered growing space. Below, the trial team shares greenhouse vegetable findings, recommendations and favorites.
Greenhouse Performers: 5 Recommended Crops
1 • TOMATOES FOR GREENHOUSE PRODUCTION
Tomatoes are one of the most widely grown crops in high tunnels and greenhouses, for several reasons. They produce earlier and later than field tomatoes. Quality is usually much higher because fruit is sheltered from weather damage such as cracking or watery flavor after heavy rain, which raises marketable yield. Covered growing also reduces diseases spread by wet leaves, such as early and late blight. Most important, tomatoes are a valuable crop in many markets and can bear steadily for months, so one planting with regular care can bring a strong return.
On the other hand, warm, humid greenhouses favor a different group of diseases, including leaf mold, powdery mildew, fusarium crown and root rot, corky root and botrytis, which spread quickly through tightly spaced indoor plants. Soilborne pathogens can build up when tomatoes are grown in the same hoophouse soil year after year; because tomatoes are so valuable, growers are often tempted to skip rotations that would break disease cycles. Tobamoviruses (tobacco mosaic virus, TMV, and tomato mosaic virus, ToMV) also tend to show worse symptoms under the reduced light of greenhouses and tunnels.
When evaluating dozens of tomatoes for greenhouse growing each year, the team looks first for four main qualities:
- Strong vigor and higher yields over a longer, warmer season than in the field.
- Resistance to the indoor diseases listed above, which are less common in field production.
- Compact, well-mannered plants that need less pruning and allow better airflow.
- The best possible flavor and texture.
Recommendations for Heated Greenhouse Production
Reliable Standards. Two dependable large, round red tomatoes combine high yields, balanced plants and good flavor: 'Geronimo' is a longtime standard with consistently heavy yields of classic red slicers around 8–10 ounces. 'Bigdena' is newer, with slightly larger, taller fruit than 'Geronimo' that give an extra slice or two. Both carry broad disease resistance and do well in heated greenhouses and high tunnels.
Top All-Around Choice. Our highest-rated tomato for heated greenhouses is 'Rebelski', its European name, also sold as 'DRW 7749'. Its glossy, bright red, lightly ribbed fruits are firm but not hard and average 7–8 ounces. Strong resistance to powdery mildew and leaf mold keeps plants healthy through a long season, and the flavor is good too.
Heirloom-style hybrids. If you like classic heirloom looks and taste, newer greenhouse introductions include 'Margold', 'Marnero', 'Marbonne', 'Marnouar', 'Cauralina'and 'Marvori', which make up our French Heritage Collection. They look and taste much like the heirlooms they resemble, but with better disease resistance and higher yield potential. Notes on three of them:
- 'Margold' captures the look and flavor of red-streaked yellow heirlooms while adding leaf mold resistance, more uniform fruit and higher marketable yield. Its very soft, juicy flesh is sweet and mild, and it resembles 'Striped German'. Excellent on sandwiches and burgers.
- 'Marnero' keeps the best traits of black heirloom tomatoes while again improving disease resistance and yield. It closely resembles 'Cherokee Purple', with very soft flesh and the rich flavor and meaty texture expected of black types. Ideal wherever raw tomato is the star, such as caprese or fresh salsa.
- 'Marbonne' is a classic French 'Marmande' type with deep red skin and a strongly ribbed shoulder. Marmande types are popular across Europe and several similar hybrids exist, but in our experience 'Marbonne' is the best of them. Like most Marmandes it ripens early, it is the highest-yielding of the French Heritage group, and its sweet flavor has broad appeal. It works in any recipe.
These heirloom-style hybrids give growers heirloom eating quality on more productive plants with better vigor and disease resistance, so plants stay healthy and bear longer. Many greenhouse growers find true heirlooms yield only a fraction of what red greenhouse beefsteaks produce, which can mean losing money. The French Heritage varieties aim to let growers profit from their best-tasting tomatoes.
Another excellent heirloom-style hybrid is 'Pink Wonder'. It resembles meaty pink heirlooms such as 'Rose' and 'Pruden's Purple', with similarly smooth texture and flavor, which is unusual in modern hybrids.
'Kakao' is a newer greenhouse tomato with a distinctive look and taste. It offers black-tomato coloring in a smaller size, with uniform round fruits of about 4½–5½ ounces. Its dark color, soft flesh and savory, almost lightly salted flavor make it instantly recognizable and easy to market.
Recommendations for Unheated Greenhouse or High Tunnel Production
For unheated structures, we recommend the varieties below. For more on unheated tomato production and the diseases to watch for, see our 12 Recommended Tomato Varieties for Hoophouse & High Tunnel Production, since the varieties and growing conditions overlap considerably.
The tomatoes listed above also do very well in unheated greenhouses and high tunnels, but some growers find their seed too expensive. For lower-tech indoor growing, good options often come from breeders in places like Italy and Spain, where tomatoes are grown in the ground under large structures. The hot, dry climate there means little leaf mold, so breeders focus on resistance to soilborne diseases and viruses and on manageable plants. Resistance to verticillium, fusarium, nematodes and TMV is so standard in these types that the industry shorthand VFNT describes the package. Their markets are demanding about fruit quality, so flavor is often better than in tomatoes bred for high-tech greenhouses. (Learn more about Tomato Pests, Diseases & Physiological Disorders…)
'BHN 589' — A semi-determinate slicer with excellent overall performance and an easy-care plant. We suggest starting with 'BHN 589' if you are new to growing determinate tomatoes under cover.
'Estiva' — 'Estiva' has been in our lineup for a long time because nothing else matches its mix of yield and quality. Bred for low-tech protected growing in southern France, it produces heavy clusters of very uniform, versatile 6–7-ounce fruit with deep red color and excellent flavor and texture. Plants are vigorous but balanced, making it well suited to unheated greenhouses, and resistance to soilborne diseases and TMV is a welcome bonus.
'Clementine' —A distinctive orange cocktail tomato that pairs nicely with the popular 'Mountain Magic'; both are available as certified organic seed. Short leaves and an open, compact habit help it fit tight spaces and stay well ventilated.
'Sunpeach'— A flavorful pink cherry tomato from Japan with leaf mold resistance and easy-to-reach clusters on a well-behaved vine. Its unusual color is great in mixed pints.
'Favorita' — Like 'Sunpeach', this small-fruited specialty has leaf mold resistance and excellent flavor. It also resists Fusarium, nematodes and TMV, on an indeterminate vine.
'Granadero' — Broad disease resistance, a compact plant and very large yields of clean fruit make 'Granadero' a top Roma choice for almost any system, including unheated greenhouses and high tunnels. It was selected for organic systems, so it is tough. It carries the VFNT package plus powdery mildew resistance, an increasingly common problem in covered tomatoes.
Grafting Tomatoes and Cucumbers for Greenhouse Production
Grafting is common in intensive systems such as high tunnels and greenhouses. You grow two sets of seedlings: the scion, chosen for fruit quality, and the rootstock, chosen for vigor and disease resistance. When both have stems of about the same thickness and their first true leaves, you cut them and join the scion top to the rootstock base with a grafting clip. The tissues fuse as they heal, creating a single grafted plant.
The main benefit of grafting is fewer disease problems, but grafted plants also tend to be more vigorous and longer-lived, with bigger yields and, notably, better flavor and eating quality.
If you can invest the time and space up front, grafting your own tomatoes or cucumbers can be very cost-effective. Hensley's carries several rootstock tomato varieties, a rootstock squash variety for grafting cucumbers, and grafting tools. For in-depth instructions, see our Tomato Grafting Webinar Resources and Cucumber Grafting Webinar Resources.
2 • Peppers for Greenhouse Production
Every pepper benefits from growing under cover, particularly when fruit is left to ripen fully. Any of our peppers can be grown in a simple tunnel and will give better fruit than in the open field.
Bell peppers are among the most common greenhouse crops. They can be tricky in the field, and premium bells can bring good prices, so they fit naturally in many greenhouses.
We carry several bell peppers bred for protected growing. In a greenhouse pepper we look for:
- Reliable fruit set in both heat and cool weather, since some varieties drop flowers at temperature extremes.
- Early maturity and attractive ripe color.
- Large, blocky fruit with good flavor and quality that commands premium prices.
- Strong vigor to keep plants growing and yielding through a long season.
Recommended Peppers
Peppers recover from poor temperatures much less readily than vigorous crops like tomatoes, so temperature control gives the best results. Some heat may be needed to avoid cold stress, and since temperatures around 95°F (35°C) or higher can make pepper pollen sterile, make sure you can vent well enough to keep the air below that.
To get the best return, consider varieties bred for low-tech tunnels. They are generally more compact and leafy than high-tech greenhouse types, though still taller with longer internodes than field peppers. More vegetative growth helps plants cope with stress. Good choices include the attractive bells 'Sprinter' (red), 'Milena' (orange), and 'Brocanto' (yellow), a set that performs well in heated and unheated tunnels alike. For early color, 'Lilo' (purple) and 'Snowball' (white) are also strong greenhouse choices.
These varieties do well with simple basket-weave trellising, but extra pruning and trellising work will increase marketable yield. For details, see our guide to Greenhouse Bell Pepper Production.
3 • Cucumbers for Greenhouse Production
Cucumbers are another leading greenhouse crop with a solid return on investment. In greenhouse and high tunnel cucumbers, we look for:
- Strong vigor for a long season.
- Good resistance to the usual indoor diseases.
- High overall yields to make the structure pay.
- Excellent eating quality: low bitterness, no seeds and thin skin, a combination that is hard to get in the field.
- Parthenocarpic and gynoecious flowering, for reliable yields without pollinators in an enclosed space.
- Fruit borne on the main vine, so plants can be trellised and pruned to a single stem.
Recommended Cucumbers
Our top greenhouse cucumber is 'Corinto,' likely the most vigorous cucumber we have grown; it can outgrow everything around it. It has good disease resistance, high yield potential and handles stress well, which helps high tunnel growers in cool shoulder seasons and midsummer heat. Add its flavor and familiar slicer shape, and it is an excellent protected-culture choice.
'Corinto' is so prolific that you will need to thin fruit to one per node so plants are not overloaded. For more, see our tech sheet on Greenhouse Cucumber Production.
For a thin-skinned, non-bitter cucumber, we like 'Katrina'. Its mild, tasty fruits appeal to children and anyone who dislikes bitterness, and plants are very productive. Fruits average 6–7", between small snacking types and the larger 'Socrates'.
'Unagi', an unusual cross between a Beit Alpha and a traditional Japanese cucumber, is our favorite greenhouse cucumber for flavor. Its smooth, seedless fruits taste so good that the Hensley's team uses it as the flavor benchmark in greenhouse trials, and it yields well with straight, glossy, uniform fruit.
'Sashimi' is a newer long Asian-type cucumber bred for greenhouses. It has the crisp, flavorful quality expected of the type and is both parthenocarpic and gynoecious, which is unusual for long Asian cucumbers. Strong powdery mildew resistance (PMR) is a big step up from older types, and fruits stay crisp and uniform across a range of sizes, so you can pick them at about 8–12".
'Itachi' adds a striking look to a market display. It is flavorful and productive, with uniform, sweet, crisp, non-bitter bright white fruits and small seed cavities.
4 • Eggplant for Greenhouse Production
Eggplant is another popular fruiting crop for greenhouses. As with peppers, most varieties suit low-tech tunnels on a simple basket-weave trellis. In more advanced greenhouses, trellising plants to a limited number of leaders gives steady, high yields of clean fruit. Greenhouse eggplant is often picked at a baby size of about ½ lb or a mini size of about ¼ lb, though fruit can be left to size up.
For growing guidance, see our tech sheet on Greenhouse Eggplant Production.
In a greenhouse eggplant we look for:
- Fast, strong growth for high yields.
- Good flavor, appearance and fruit quality.
- Tolerance of wide temperature swings.
Recommended Eggplant
'Gaudi' performs well indoors and out, producing heavy yields of glossy, teardrop-shaped fruit. Spineless, adaptable and stress-tolerant, it holds its deep black color through and after harvest.
'Annina' also does well in high tunnels and open fields. Its spineless fruits have eye-catching purple and white stripes that look great alone or sold alongside black and white types, with high yields and excellent uniformity.
'Aretussa' is a smooth white eggplant with a slim teardrop shape and spineless green calyx. Plants produce uniform fruit heavily in heated and unheated structures and in the field. White eggplants are often sweeter and less bitter, and this one is sweet and creamy with excellent flavor.
'Turkish Delight' is parthenocarpic, so fruits stay seedless in an enclosed greenhouse. It yields heavily, with uniform, straight, spineless fruit and rich flavor.
5 • Lettuce for Greenhouse Production
Lettuce prefers cool temperatures and lower light, which makes it ideal for winter greenhouses. It is also flexible in its needs and can be quite profitable. However, the very cool, dim conditions in low-tech winter greenhouses and high tunnels can lead to disease, especially downy mildew, and to poor color in red varieties.
Recommended Lettuce
Years of greenhouse trials have shaped a solid selection of lettuce varieties for winter growing. These two are a good place to start.
'Five Star Greenhouse Lettuce Mix'. This mix tackles both problems above. Its varieties were chosen for downy mildew resistance and strong color, and for even growth rates. It is our top choice for baby leaf and salad mix during short winter days.
Salanova® Lettuce. The Salanova varieties also stand out in greenhouse trials. To learn more about this productive, versatile lettuce, see our brochure on Salanova, the Ultimate Efficiency Lettuce.
More Resources on Greenhouse Varieties & Cultural Practices
Articles
- Why Grow in a Greenhouse? Basics & Benefits Article
- Beginning & Intermediate Controlled Environment Agriculture (CEA) • Advances in Greenhouse Crop Production Article
- Cucumber Grafting: Advantages, Materials, Technique Article
- Trellising Hoophouse Tomatoes Article
- Growing Fruit Under Cover Article
Webinars
Tech Sheets
- Top-Grafting Tomatoes • Advantages, Materials, Technique Tech Sheet PDF
- Side-Grafting Tomatoes • Advantages, Materials, Technique Tech Sheet PDF
- Grafting Cucumbers • Advantages, Materials, Technique Tech Sheet PDF
- Greenhouse Cucumber Production Tech Sheet PDF
- Cucumber Types & Terminology Tech Sheet PDF
- Greenhouse Eggplant Production Tech Sheet PDF
- Greenhouse Bell Pepper Production Tech Sheet PDF
