Grow Tomatoes in a Hoop House

Updated: November 22, 2019

Since you’re reading this article, you probably want to know if it’s better to grow tomatoes in a hoop house? The answer is yes.

The biggest reason for backyard gardeners to use a hoop house or a high tunnel (another name for a hoop house) is that you can harvest vine-ripened tomatoes as much as six weeks sooner than if you grew them outside.

And you can do this with only the sun — no added heat required.

That’s a pretty big incentive for those who want neighborhood bragging rights for the first tomato of the season. It also means spending less on tasteless grocery store tomatoes.

Related: How to Grow Cucumbers in a Hoop House.

Let’s take a sec to get the legal words out of the way. This article may contain affiliate links. That means if you click and buy from my partners, I will make a tiny amount of money. This in no way affects my recommendations.

Why grow tomatoes in a hoop house?

Getting the first ripe tomato in the neighborhood is a good reason to consider getting a backyard hoop house kit.

One of these kits will allow you to easily build your own hoop house. Then you can:

• Extend the tomato growing season two to three months (as much as six weeks at the beginning and six week at the end).
• Protect tomatoes from insect pests and varmints, including hornworms and ground hogs (without the need for a fence).
• Control moisture on plants, which helps to prevent mold and fungal diseases, extending your plant’s life.
• Control moisture in the soil, which reduces tomato cracking and improves flavor.
• Increase air and soil temperatures so that tomatoes ripen more quickly.

Why you may not want to grow tomatoes in a hoop house

Still, it isn’t all roses (pun intended) when you grow tomatoes in a high tunnel. There are some disadvantages:

• Diseases are problematic. Once a disease gets into the hoop house, you may have to move the whole thing to a new location.
• High heat during the summer can make it uncomfortable. You have to prune, weed, water, etc. before the sun starts beating down.
• Ventilation is key. Some varieties of tomatoes won’t set fruit when the temperature is too high.
• Indeterminate tomato plants require heavy pruning to keep them from taking up too much valuable space.
• Trellising is required to protect tomatoes and plants from the water / dirt and the associated diseases.

By my calculation, the advantages outweigh the disadvantages.

Read on for a comprehensive guide to growing tomatoes in backyard hoop houses or, as market farmers often call them, high tunnels.

Note that a hoop house and a high tunnel are pretty much the same thing. Some people call them polytunnels. Backyard growers tend to call them greenhouses.

Related: How to Reuse Windows in the Garden

Cold frames, row covers, hoop houses, polytunnels and high tunnels are all techniques of a plant growing method called protected culture. You’ve heard of “agriculture” and probably “aquaculture.” Lately, a lot of backyard growers are also talking about “permaculture.” “Protected culture” is like those. It refers to growing plants using protection from the elements.

Market farmers have been using protected culture for some time now. High tunnels help them bring produce to market sooner.

They will sometimes grow tomatoes in a hoop house before it’s warm enough outside. So they have to heat their high tunnels to keep the tomato plants in the temperature sweet spot.

Tomatoes like it best when the temperature is between 70 and 90 degrees Fahrenheit. When you grow tomatoes in a hoop house try to keep the temperature in this range.

Trellising & pruning are important

Since space is tight in a backyard hoop house, growing vertical and pruning is especially important. To efficiently use space and keep tomatoes off the ground, I use the string method of trellising. Plus, I prune heavily to keep plants from getting wide and too dense with foliage .

The string method works like this:

1. Attach a string to the hoop house support directly over the plant, making sure there’s at least 5 feet of space from the ground to the top of the hoop house.
2. Run the string down from the top of the support to the base of the plant.
3. Tie the string around the very bottom of the stock or stake it in the ground.
4. Wrap the string around the plant (especially under the branches) as it grows.
5. Prune all branches off ALMOST up to the lowest cluster of tomatoes. Leave one branch under the cluster.
6. Remove suckers. This encourages the plant to grow tall.
7. Lower the tomato plant when it reaches the top of the hoop house. Do this by letting out more string. This gives the tomato plant more room to grow skyward.
8. Make sure the tomato clusters are at least six inches off the ground (more if needed to prevent them from getting wet or dirty).
9. Coil the branchless vines on the ground below the plant canopy.

I use the Growers Edge Lock-N-Release Spool Plant Support with Twine to trellis my plants. It gives me the confidence that the string won’t somehow drop my plant, which would be bad.

Just as important as trellising is pruning. According to the experts at the Extension at the University of Minnesota, pruning hoop house tomatoes will:

• Increase fruit size
• Promote earlier harvest
• Reduce incidence of disease
• Reduce grey wall (blotchy tomato ripening)
• Increase air flow

When pruning indeterminate tomato varieties, you should:

• Wait for the first tomato to grow to the size of a nickel
• Prune everything below the lowest flower cluster
• Remove all other suckers during growing season before they reach four inches long
• Prune to one leader (center stem)

If you prune to have two stems, you will have more tomatoes. But I don’t recommend it because it makes it hard to trellis using the string method.

Related: Better Tomatoes with Walls O Water.

Pruning sanitation is important. Always prune with sharp, clean tools. If there are stunted or diseased plants, do not prune. Pull them out instead.

If you tend to have problems with disease, I recommend disinfecting your pruning tools. Fill a bucket full of Lysol or Simple Green D and soak the tool for a couple of minutes. Then rinse thoroughly (away from your garden) before using.

Best hoop house varieties

As you might imagine, there is some debate about which varieties are best. I believe tomato seed sellers don’t want you to use heirlooms because you can save your own tomato seeds.

I believe you can grow any tomato that meets the following criteria:

1. Heat tolerant: It’s going to get hot inside the hoop house, even with maximum ventilation.
2. Indeterminate: Some people prefer determinate varieties because they naturally take up less space. However, if you trellis and prune indeterminate tomatoes, they’ll do fine. Plus, with indeterminate varieties ripening will be spread out over time. This is good for slicing tomatoes because you can only eat so many at one sitting. But if you are making sauce, determinate will give you a lot all at once, which is good.
3. Heirlooms: The most common reason heirloom tomatoes crack is because of inconsistent watering. Hoop house tomatoes will crack less because you can better control how much water you add to the soil. (It doesn’t rain inside the hoop house.) Still, tomato root systems are big and will grow beyond the enclosure. So there will be some cracking after a heavy rain.

That’s it. Any tomato you’d grow in the field will be better in the hoop house.

I find that Brandywine and Pineapple heirloom tomatoes work really well. They may end up a little smaller than when grown outside. This is because they ripen faster and don’t have enough time to grow bigger.

One important point to remember: I find that even the most heat tolerant varieties will suffer blossom drop if it stays above 80 degrees at night. So during the summer add as much ventilation as you can.

Moving the high tunnel

One of the biggest advantages of backyard hoop houses is that they’re small and two people can move them easily.

This is a lifesaver when you have a problem with the soil in the hoop house. When this happens, just move it.

Soil problems are more likely to happen in the enclosed hoop house space, although I haven’t had this problem yet. Some high tunnel growers change the soil every couple of years. I find it easier to just move it.

Double protected culture

If there’s only one idea that you take away from this article, it should be this: There is an easy trick to get tomatoes EVEN SOONER. I call it double protected culture.

Do this: Plant your tomatoes in a cold frame that sits inside a hoop house. This will allow your plants to stay toasty even before it gets warm outside. Two layers of protection trap heat much better, so you can plant sooner.

If you use this method, you must open the cold frame when it gets too hot for young plants. Otherwise they will burn up.

You’d be surprised how hot it can get inside a double protected culture environment when the sun is shining.

When should you plant?

I live in hardiness zone 5b. This is my schedule for planting tomatoes:

February 10 — Plant seeds indoors.
February 20 — Move seedlings to hoop house during the day if sunny, inside at night.
March xx — Transplant to larger pots, continue moving plants in & out.
April xx — Transplant to ground in cold frame inside hoop house.
May 15 — Open cold frame when frost danger is gone or when too hot.

Tomato plants grown in the hoop house in my area will last into November. My last ripened tomato was November 4. But keep in mind, even hoop house tomatoes will ripen very slowly when it gets late in the year.

Hornworm moths & hornets

Two big challenges in my area are keeping hornworm moths and hornets out of the hoop house. So when I grow tomatoes in a hoop house, I try to keep the windows and other ventilation openings screened to keep these pests out.

I find that hornets like to build nests in the warm hoop house. This can be a real problem for organic growers because you don’t want to spay pesticides, especially inside an enclosed area.

Pollinating tomatoes

If you screen hornworms and hornets out, you are also going to prevent pollinators from coming in. So you’ll have to hand pollinate the tomato flowers.

Fortunately, this is easy. All you have to do is gently tap on each flower to get the pollen where it needs to be. Do this often to increase success.

I do this several times for each flower to make sure they get pollinated. You will want to pollinate your flowers as soon as they appear. This helps tomatoes start sooner and ripen early.

Often, early flowers go unpollinated. Not good.

The sooner you pollinate, the sooner you will eat tomatoes.

Some people shake their plants to spread the pollen. Market growers that have tons of plants will use fans. But because you only have a few flowers, tapping works better.

Weed barrier fabric & green mulch

Backyard hoop house growers will want to keep their indeterminate varieties healthy and growing for as long as possible. A little cold weather no longer means the end of your growing season.

So if plants die because of disease, it’s a real shame.

So disease prevention is more important. With this in mind, many high tunnel growers use weed barrier fabric to prevent water splashing onto the plant and spreading disease.

But I don’t use weed barrier fabric for two reasons:

First, I have a problem with voles. Unfortunately, voles love tunneling under weed barrier fabric. I do everything I can not to attract voles. This means I don’t do anything to make their life easier.

Second, I don’t like the idea of plastic leaching chemicals into the soil, especially if it’s not food grade plastic. Whenever possible I don’t use plastic.

Instead, I use green mulch (usually arugula) that doesn’t compete too much with the tomato plants. Arugula works well to prevent splashing. Plus the voles don’t seem to like it.

When the arugula starts to get big, I cut it back to keep things orderly and encourage new arugula growth.

Sum it up

Hoop house growing allows you to ripen tomatoes sooner in the season and keep them growing later in the year. You also benefit from fewer pest problems.

So if you enjoy tomato growing, why not try an inexpensive, backyard hoop house? Get started today.

Other articles that may interest you:

1. I Shopped for Small Hoop House Kits. Here’s what I learned
2. Winter Sowing Plus a Cold Frame or Hoop House
3. Growing Lettuce in Winter

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