Caring for Tomatoes

For tomato lovers, picking a warm, flavourful tomato right off the plant for a sandwich, burger, or salad is a sure sign of summer!  I eagerly await the day the first fruit begins to turn red, knowing that I am a day or two away from the first of many toasted tomato sandwiches for the season!

By the end of June, your tomato plants should be in the ground or pot, staked, and well on their way to producing fruit. But how do you keep your plants healthy all summer so that you can maximize your investment? Here are a few tips to help keep your tomato sandwiches coming until frost!

Water

Water early in the morning and water deeply. For tomatoes, consistent moisture is best.

Keep the water on the ground, not on the foliage. This is important because damp foliage can lead to diseases like early blight, which can ultimately cause the entire plant to die. Mulching around the base of plants will reduce the amount of water that can splash up onto the leaves. A soaker hose or drip line is also a great way to ensure that water stays on the ground, rather than on the plant.

Pruning

Reducing the amount of foliage on a tomato plant is necessary for a couple of reasons: good air flow, which reduces the chance of powdery mildew forming, and less foliage means that the plant can send energy to growing fruit instead of lots of leaves.

Follow these easy steps when you prune your tomato plants:

• Before you begin, remember to follow the rule for pruning - no more than ⅓ of a plant should be removed at a time. 

• Use clean scissors or pruning shears to cut the leaves off the bottom of the plant. Remove any leaves that are touching the ground. These are particularly susceptible to mildew formation.

When fruit starts forming, remove the leaves from the bottom of the plant up to the first or lowest fruit.

Remove suckers ongoingly. What are suckers? When you look at your tomato plant, you will see the main stem that comes up from the ground, and branches of leaves that come out of the main stem. As the plant grows, suckers begin to form in the “Y” between the main stem and a branch of leaves. Suckers won’t harm a plant; they just make it very unruly and reduce airflow.

If your tomatoes are indeterminate (growing into a tall vine), remove the top of the plant when frost is forecasted at the end of the season. Topping the plant allows energy to ripen the fruit that’s already set, rather than being used to continue growing the vine.

NOTE: Some gardeners like to leave suckers on determinate tomato plants as this can increase the yield.

TIP: Tomatoes ripen from the inside out. That means that by the time you see fruit beginning to flush on the outside, the inside is already ripe. If you have competition for tomatoes from pesky critters, or when there’s a chance of frost in the weather forecast, you can pick fruit that has just begun to turn colour and leave it on the kitchen counter to continue to ripen. 

Fertilizer

Using organic material is one of the best ways to feed your crop. A good layer of compost, 1-2 inches, in the spring when you’re planting and again in the fall each year is one of the best ways to improve your soil structure in the garden, and it also adds lots of nutrition. 

If you missed this step when planting your garden, you can always add a layer of compost around your plants or use other organic fertilizers, such as compost tea, seaweed, worm castings, or fish emulsion.

Alternatively, you can use a fertilizer that’s formulated especially for tomatoes - these usually have a ratio like 3-4-6 or 4-7-10. Follow label directions for amounts and err on the side of caution. Using less fertilizer is always better than using too much, as an excess can stress the plant and make it more prone to disease.

Following these simple steps for tomato care will help to ensure your plants stay healthy and producing fruit, but if you should have problems, here are some great resources to identify tomato issues:

• Ontario.ca: Bacterial diseases of tomato: bacterial spot, bacterial speck and bacterial canker
• Guelph.ca: Healthy Landscapes – Plant List Native and Drought-Tolerant Plants