Growing Tomatoes in a Cold-Climate Garden Without a Greenhouse

Reader Contribution by Kat Ludlam and Willow Creek Farm
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Harvested tomatoes by Kat Ludlam

As the majority of gardeners in America are planting their seeds and enjoying time in their gardens, many of us are cooped up in our houses, snow falling outside, as we continue to pour over seed catalogs and dream of warm weather. Living in a short-season/cold climate might make you feel like you can’t grow tomatoes without a greenhouse. We used to think that ourselves. We live in the high-altitude Rockies, where we have a 10-12 week growing season frost-to-frost, and our nights during the summer regularly dip down to the 40s Fahrenheit. But over the years we have learned through trial and error, and ideas from others, that it is absolutely possible to grow and enjoy tomatoes from a short-season/cold climate garden without the use of a greenhouse.

Pick the Right Varieties

The first step to success is to choose good varieties for your climate. It is so easy to get caught up in the beautiful seed magazine and want to try a little of this and a little of that. You can try different varieties, just make sure you are picking the fastest-to-harvest varieties that tolerate the colder temperatures. We have found that the varieties that originated in Siberia and Russia are a good place to start and they generally do very well for us. Our favorite varieties include Mount Roma, Mother Russia, Russian Yellow, and Long Keeper. Seeds Trust has a great selection of tomato varieties for cold climates.

Start Indoors

When you have a very short growing season, starting your plants indoors is a necessity. We found that using a light shelf unit worked much better than our windows. My husband was able to build us one pretty easily and it saved us a lot of money. I start our tomatoes indoors about 10 weeks before our average last frost.

 Start indoors with plant lights by Kat Ludlam

Once they have their first set of real leaves, we transplant them to bigger containers and continue to keep them under the lights.

Fragile seedlings by Kat Ludlam

A week before they are going to be planted outdoors, we harden them off. To do this we wait until the sun is up and warm and then we place them outside in a splotchy shaded area. The first day they stay out for about 30 minutes, the second day an hour, and so on as we work them up to being able to handle a full 8-hour day out in the splotchy shade. We bring them in if the weather is windy, or it starts to rain. And when they come in, they are no longer under the lights, they are just next to windows in the house. By doing this they will become “hardened off” and thus be able to survive outdoors better.

Transplant Early, With Protection

We transplant the seedlings to the garden about 1 month before our average last frost. The reason we can do this is that we use Wall-o-Waters (WOWs) to protect them from the frosts for that month. We have had our WOWs buried in 4 feet of snow, and the tomatoes in them still survive.

Thermal protection with wall-o-waters by Kat Ludlam

It is important to prepare the WOWs at least 24 hours ahead of time, so the temperature of the water in them can stabilize before you put the seedlings in them. Fill them from your hose (the easiest way is the put the WOW around a 5-gallon bucket to support it during the filling).

Filling wall-o-water by Kat Ludlam

Then place them in the garden where you want them and squeeze the top 1/3 of them, causing the water to come out of that top section and forming a teepee shape with the WOW.

Wall-o-waters by Kat Ludlam

After 24 hours the temperature in the WOW will have stabilized and you can plant your seedlings in the center of the WOW. We have found that ours do best if we first plant them at the time of day that the section of the garden they are in is in some shade, which for us is early morning or late afternoon.

Ttomato seedling in wall-o-water by Kat Ludlam

Once the threat of frost has passed, and the tomato plants have grown so much that they are filling up the WOWs, we remove them and put a cage around the plant.

TIP: Helping Your Wall-O-Waters Last Longer

We have been using WOWs for many years to garden in our cold climate. Over time, the wear and tear of use, plus the effects of the sun on the plastic, will break down the WOW and it will begin to get holes. We have found that just because a WOW has a hole or two, doesn’t mean it can’t continue to be used. We take our most damaged one and cut it carefully, saving any of the tubes that don’t have holes. We then insert those tubes in to the tubes on other WOWs that have holes, doubling them up so they won’t leak. This has helped us keep using the WOWs for many many years. We are still using WOWs that are over 10 years old and going strong.

Wall-o-water tube by Kat Ludlam


Patched wall-o-water by Kat Ludlam

Harvest Before First Frost

As autumn approaches, we begin to watch the weather closely for our first frost. At this point we are harvesting a few ripe tomatoes, but most of them are still green. The day before the first frost we harvest all the tomatoes, cutting them off the plants, leaving about an inch or so of stem on them.

Harvested green tomatoes by Kat Ludlam

We then put them in the basement in our root cellar racks.

Tomatoes ripening in racks by Kat Ludlam

You can put them anywhere that is cool and dry, just be sure to lay them out in a single layer.  Before we built our root cellar racks, we set up folding tables and put the tomatoes out in a single layer on them in the basement.

Over the next weeks, the tomatoes will ripen and are great for fresh use or for cooking or canning. We harvest our tomatoes green in early September and are eating and canning them all throughout the fall as they ripen. Our longest keeping varieties are ripening in early December, and we have even enjoyed “fresh” tomatoes, from our garden, at Christmas – months after the first frost hit our area.

You don’t need a greenhouse to grow delicious tomatoes in a short-season cold-climate garden. With careful planning and a few tips from my high-altitude garden, you will overcome your climate challenges and enjoy fresh tomatoes all through autumn and into winter. To read more about how we successfully garden in our climate, check out my blog series “High-Altitude Cold-Climate Gardening.”

Kat Ludlam is a high-altitude homesteader and owner of Willow Creek Farm in the Colorado Rockies, where she breeds landrace sheep, chickens, and crops accustomed to elevation. Check out Kat’s custom fiber-processing business, Willow Creek Fiber Mill, and read all of Kat’s MOTHER EARTH NEWS posts here.

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