Tips on Growing Hobby Greenhouse Tomatoes

All the guys want big tomatoes. It’s just my personal observation as I sell tomato plants this spring at markets and also out of my greenhouse. I ran out of the variety “Aussie” first that produces giant three pound tomatoes. Meanwhile the cute “Jasper” variety with its early but small red cherry fruit are waiting in their tray to be noticed by customers.

It is spring and everyone with a greenhouse is getting a jump on the season while those without are looking to buy replacement plants after yet another late frost.

We are in a time of possible food scarcity and no one seems to want the miniature version of food. They want heavy fruit, big plants and prolonged heavy harvests. The truth is most tomato plants will produce about twenty pounds of fruit per plant per season according to one recent interview I did with a commercial tomato farmer.

So you can get 350 cherry tomatoes or 6 three-pound tomatoes per plant in an average season. Of course, this will vary with length of season and how you heat or provide light in your greenhouse. The more you give, the more you get.  In an average 8×12 greenhouse, you can plant 6-8 tomato plants per sidewall. You want to give them at least 14” of breathing room on either side and force them to grow up the wall.

As a hobby grower what is the best way to boost your production beyond the averages? Here are some pointers:

  1. Provide some early season heat in your greenhouse to get the soil warm and plants established early. In my case I use soil warming cables to boost the soil temperatures and get the plants growing fast. Plus, I cover the plants at night with Agribon floating row cover to keep the heat in when the temperatures are coldest. Agribon-50 provides up to 8 degrees of frost protection over and above what your greenhouse already gives you but it also blocks out 50% of the light so I only use it at night.

2. Start with a variety of plants so you have some tomatoes for slicing (Aussie) on your huge pieces of homemade bread plus some cherry-size fruits (Jasper, Sweet 100, Chocolate Sprinkles) for roasting and adding to salads. Ideally you will also have some drier Roma-style fruit like Juliet for making tomato sauces for your freezer and some long keeper varieties like Clare’s Longkeeper for storing and eating well past harvest season. I ate my last Clare tomato in March this year even though I harvested it in late September.

3. Check to see if plants need water on a daily basis. Plants that dry out excessively and wilt are more likely to get blossom-end rot (a black end on the part of the tomato opposite from where it is attached to stem.) This ruins the look and the storage ability of plants. This is often blamed on lack of Calcium but is more often due to erratic watering – especially in pots.

4. I start pruning tomatoes as soon as they start sending out suckers. My goal is to fill the whole vertical space in my greenhouse. I space the plants about 14 inches apart and want the plants to grow up and not out. As the plant grows up it produces fruiting trusses. I remove the leaves below the lowest truss and try to remove side branches as well. I run a string from the top of the greenhouse down to the ground and wrap the stems around the string as they grow. No need to tie them or attach them to the string. Just twist them around string as they grow.



5. I use organic fertilizers like Ag lime and alfalfa pellets so there is slow release and steady access to minerals as the plant needs them. This means growth is steady and long.

6. Tomatoes are fabulous but I start hardy winter seedlings in my house in trays so the day I take out my tomatoes I can refresh the soil with compost and plant the hardy mustard greens, kale and spinach that will take me through the winter while I eat and store my winter crops of tomatoes.

Remember to make hay while the sun shines and can, preserve and freeze your tomato crops.  It’s the best way to ensure home grown produce all year long.

For more great tips from Donna, visit www.donnabalzer.com.

You can also read Donna’s gardening books: No Guff Vegetable Gardening with Steven Biggs and her just released Gardener’s Gratitude Journal:  Part Diary, Part Personal Growing Guide.

Donna Balzer