GardenLine | Vegetables | Tomato Production for Saskatchewan's Gardeners (Part 1)

Nothing compares with the taste of your own fresh-picked tomato, so very few people consider a vegetable garden complete until at least a few tomato plants are included. The following are a few tips for successful tomato establishment.

Start with a Healthy Transplant

As warm-season crops, tomatoes require a long growing season to mature. The best crop therefore begins with healthy transplants. These transplants have traditionally either been started at home, or purchased from greenhouses in spring. When buying your transplants remember that the largest plants are not necessarily the best. A good transplant will be dark green in colour and not much more than 20 cm tall. The stem should be straight and stalky enough that the plants are very sturdy. The plant should have healthy white root tips, but should not be rootbound. This is easy to see if you pop a plant out of the cell pack. Also, you should resist the temptation to buy those plants that already have flowers or fruits developing. This promise of earlier tomatoes can be quite misleading, as larger plants with flowers and fruit will usually fall behind the smaller ones at establishment time. If your home-grown transplants have flowers, you are better off in the long run to remove them so the plants will not be diverting energy from root establishment to fruit production. Very often, home-grown tomato transplants also become somewhat taller than the ideal size. Such plants usually have a group of leaves at the top of a relatively bare stem. When planting tall transplants, you should dig them deep enough so that only the leafy tops are above ground. This will reduce the chance of the plants breaking in the wind, and since the below- ground portion of stem will quickly begin to develop roots, the stem can help in plant establishment.

Transplant shock and hardening off

When a plant is taken from its cosy greenhouse environment and abruptly forced to face the harsh realities of the real world, it will often react by entering a condition known as transplant shock. If this happens, all growth stops for a period of one or more weeks, and in serious cases the plant dies. To avoid transplant shock, young plants should be "hardened off" for a week to ten days before the anticipated date of transplanting. In its simplest sense, hardening off can be thought of as a horticultural version of the philosophy: That which doesn't kill us makes us strong. Over a period of days, young plants are subjected to a greater and greater degree of stress, permitting them to adapt slowly to intense light, stronger wind and some drought. To start the process your plants should first be placed outside in a partially shaded location where they will receive good shelter-the east side of a house makes a good spot to start the process. Every few days the plants can be moved to a slightly more exposed location until they are spending the day in a nearly exposed site. During the process, the plants should be kept moist but not wet. This can be a bit tricky if you are leaving them out all day while you're at work because the little cell packs dry much more quickly outside than they do in the house. A slight drought by the end of each day is ideal, but if you are not sure they will make it until you get home, you are better off to give them a good watering each morning. More than one gardener has returned home to discover crisp little tomato plants by the back door, resulting in yet another trip to the greenhouse. Of course, throughout the process of hardening off, the plants should be brought inside if there is any danger of frost.

The Day of the Big Move.

After all danger of frost has passed transplants can be planted in the garden. Typically the May 24th weekend is the time for this, but with the cold spring of 1995, many people have opted to wait a week or more before transplanting.

The more thoroughly the soil has been worked prior to transplanting, the better the plants will do, and the easier the job will be. It cannot be strongly enough stressed that a small plant that is being pressed into a tiny hole chiselled into rock- hard soil has far less of a chance of survival than one that is being placed into loose, well-worked soil. When transplanting it is very important that the entire peat plug be is covered. If any part of the peat plug is left exposed, it will act as a wick, drawing moisture out of the ground and drying the roots. If you find that the plant has become root bound in the plug, you should gently break up the root ball. As distressing a thought as this may be for you, breaking up the tight circles of roots actually helps the plant establish because the broken roots will branch outward into the soil rather than continuing to circle in the established pattern. A light fertilizing with 20-20-20 is helpful soon after planting.

If possible, try to transplant on a cool cloudy day. The worst time to transplant is during the hottest part of a bright sunny day. At this time, the plant is most susceptible to drought stress, and leaves can quickly dry to the point of crispness. A few days of cool damp weather following transplanting doesn't hurt things at all, but whether it is cool or bright, you should provide frequent thorough waterings.

Many people find it useful to place old milk cartons or other protective surroundings around the plants. These serve two functions. Above ground, they protect the young plant from wind and bright sun immediately after transplanting. Below ground, they help to deflect the underground advances of cutworms that might be taking place just below the soil surface. Once the tops of the plants have emerged from these enclosures, the containers can be removed.

Part two will deal with the summertime care and harvest of your garden tomatoes.

© 1995 Jackie Bantle

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Sustainable horticultural information, offered free of charge to the public with the support of the University of Saskatchewan Extension Division, the Department of Plant Sciences and the Provincial Government.