Mark Cullen Tips for Growing Tomatoes


Tomatoes are the most popular garden vegetable in Canada by far. They are easy to grow just about anywhere there is heat and sun. There is a huge variety of tomatoes to choose from, in colours ranging from white, yellow, orange, red, green and purple. I grow over 200 tomatoes and 20 different varieties each year. My favourite varieties include ‘Sweet Million’ cherry tomatoes, which work well in containers; ‘Big Boy’, is a good medium-sized, disease-resistant tomato; and any of the big juicy beefsteak hybrid tomatoes. If you are planning to preserve tomatoes for winter use you must grow some San Marzano or Roma paste tomatoes.

Tips for Growing Tomatoes 03

Every summer, gardeners request my secret recipe for growing tomatoes. I follow a simple 4-step approach which brings great results.

  1. I start with a bushel of finished compost added to every planting hole. Tomatoes like consistent moisture and do not like to dry out or to sit in water. Compost drains easily and retains moisture. Biomax ® Composted Manures are a great choice for your tomato plants. These manures are approved by the Compost Council of Canada.
  2. Plant young tomato plants deeply. Choose seedlings with dark leaves and a short, sturdy stem.  Plant the seedlings at least up to their first leaves and so that the soil covers this area. New roots will develop along the stem, producing a stronger plant.  Put seedlings in the ground once the temperatures are warm (a minimum 20°C throughout the day and night – generally a week after the last frost date. Pick the brightest and hottest location. Tomatoes like plenty of sun – a full eight hours a day, in fact. They also like heat and shelter from the wind.
  3. Water tomato plants well and but allow the top 5 cm. of the soil to dry out once the plants have matured. Once your tomato plants are established, spread straw mulch about 25 cm deep per plant. Straw mulch helps to retain needed moisture during the hot, dry spells of summer and reduces weeds dramatically – by up to 90%.
  4. Tomato plants are heavy feeders. They will get most of their nutrition for the compost used at planting time.  I recommend that you give the plants an extra boost with PRO-MIX® Tomato, Vegetable & Fruit 9-16-16.  This is an organic based water soluble plant food with Mycoactive, an organic growth enhancer.
  5. Stake each plant with a spiral stake. This will double your crop. These are 6’ long and provide support for the tomato plant as it grows. There is no need to tie the plant onto the support structure. Simply encourage the new growth to wrap around the spiral and let nature take care of the rest. Tomato plants send out “suckers” directly above the main side branches. These suckers can bear fruit but they tend to rob the plant of nutrients and cause smaller fruit.  Follow the main stem up from the ground and look for suckers to emerge where the side branches meet the stem. Remove these suckers as they appear.

And finally, a bonus tip. All tomato plants should be sprayed with Bordo Mixture in July to prevent early blight on tomato plants. If you have ever watched your healthy tomato plants turn yellow almost overnight, starting with the bottom leaves, you have experienced the devastation caused by blight. Bordo, a natural remedy, is a preventative treatment and must be applied before symptoms of early blight are noticed.

Harvest often (words to live by!) and do not allow fruit to rot on the plants. This will slow fruit production and is an invitation to insects and diseases.

Tomatoes in Containers

If you are strapped for space but love tomatoes, it is possible to grow them in containers.

A half barrel is a great choice for growing tomatoes. It is wide and deep enough to support a good healthy tomato plant.  Tomatoes are heavy feeders and require a generous quantity of nutrient-rich soil. Use PRO-MIX® Premium Vegetable and Herb mix. It contains an organic fertilizer that gradually feeds plants for up to 3 months.

Drainage is extremely important when growing tomatoes in a container. Drill 7 or 8, half inch holes in the bottom of the barrel to ensure good drainage. Line the bottom of the barrel with a garden fabric to stop the soil from escaping. Add a layer of gravel to keep the drainage holes free from debris. Fill the container with PRO-MIX® Vegetable and Herb Mix and begin planting.



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