By Joyce Ower, WSU Master Gardener
Successfully growing heat-loving tomatoes can be a challenge in our cool climate. Your chances of harvesting ripe, red tomatoes before summer’s end can be enhanced if you plan ahead and use some or all of the tips that are covered in this article.
First, and most important, is to choose a cultivar (variety) that matures fast. This is true not only for tomatoes but all vegetables you plant because our growing season is much shorter than locales to the south. When you go to buy a seedling or seed packet, look to see the number of days until harvest that is listed with the plant description. Choose those with the shortest number of days.
If you plan to start with seeds, you need to get your tomatoes started inside now. If you plan to buy seedlings, wait until frost is no longer a possibility.
Once you’re ready to plant, remember the real estate maxim: Location, Location, Location. Plant your tomatoes where they will get maximum sunlight (and warmth). One year I planted all of my tomatoes in very large black plastic pots set on a wagon which I moved around to access the sun. At night, I left the wagon on the concrete patio where residual heat would radiate up to them. This worked well but required a lot of time so I’ve tried other strategies.
One strategy is to dig a trench, not a hole, to plant in. Lay the seedling in the trench and fill all but the last several inches with soil. The exposed tip will soon turn upright and grow straight up while the buried portion will grow roots from the former stem, close to the surface where the soil is warmer. It takes a bit of courage to bury those healthy branches and leaves but the result is well worth it.
Another strategy I’ve tried, and plan to do again this year, is to cover the garden bed with black plastic. Then I cut a hole (or an X) in the plastic and plant the tomato seedling through the hole. The black plastic absorbs the heat from the sun and keeps the soil warm. An added bonus is that there is no weeding to do and the need to water is reduced due to less evaporation.
You can also put mini “greenhouses” over your seedlings if a cold night is forecast. Cut out the bottom of a gallon milk jug and pop it over the young plant. Of course it needs to be sunk into soil to keep it from blowing off and you will need to remember to remove it the next day because if it’s sunny, it can cook your tender plant. If you can access the heavy plastic water jugs (5-gallon size), they make great greenhouses for slightly larger plants once the bottom is removed.
Using the above strategies should yield you a bountiful crop of tomatoes. And don’t despair if you still have green tomatoes at the end of the growing season when frost threatens. Pick all your tomatoes and bring them inside to ripen. I picked the last of my tomatoes in October of last year and was enjoying them as they ripened up until Christmas!
Master Gardeners are available to answer home gardening questions locally through the Wahkiakum County WSU Extension Office on River Street in Cathlamet. Phone: 795-3278. Ask to have a master gardener contact you. There will also occasionally be master gardeners at the Community Garden located in Erickson Park here in town on Columbia Street.