Chapter 9
Transplanting into the Garden
Be certain that your plants have been hardened off before placing them outside and exposing them to the elements. Plants can be moved to the garden, with protection, two weeks prior to the last frost date in your area; but unprotected plants must not go outside until after the final frost date (June 1st here in Zone 5B). Even then, there could be a night or two early in the growing season when the plants might need to be covered and protected from the weather. Watch the weather forecast closely as tomato plants do not tolerate cold weather and will die if exposed to low temperatures without protection.
Transplant only the strongest of your plants. An ideal transplant should be at least 8 to 12 inches tall with four to six true leaves. The plant should be wider than tall, stocky and hardened off. Plants that have not been conditioned to the outside environment prior to transplanting are very susceptible to cold, heat, wind, and bright sunlight.
When selecting your planting date, be aware that tomatoes will not do well until the daytime air temperatures are greater than 60˚, nighttime air temperatures are greater than 50˚, and soil temperature is at least 55˚ to 60˚. Planting tomatoes out too early gives little advantage and places the plants at risk of cold injury. Tomato plants will be set back or killed by low temperatures. One week with night air temperature below 55˚ will stunt plant growth.
When selecting a planting site, keep in mind that tomatoes do best in full sun. The more sun your plants get the better. However, tomato plants do not require high temperatures, and will grow well with air temperatures as low as 60˚.
A soil temperature range of 70˚ to 80˚ is optimal for growing tomatoes. The ideal soil temperature is 75˚. Minimal growth occurs at a soil temperature of 60˚. An air temperature range of 60˚ to 90˚ is optimal for growing tomatoes and the ideal air temperature is 86˚. Minimal growth occurs at 60˚ and growth stops at 96˚. Black plastic mulch will increase soil temperature by 5˚. Using leaves or straw as mulch will lower the soil temperature by 5˚. Though plants can tolerate an air temperature of 50˚, one week of air temperatures at less than 55˚ may stunt tomato growth. A plant will not grow in a cold location no matter how much sunlight it gets.
When you do transplant, remove the lowest leaves from the plant. Try to transplant on a cloudy day and in the late afternoon to avoid sunburn, or shield your plants with light weight row covering or shade cloth. Giant tomato plants should be placed at least 3 feet apart. Crowding plants will reduce the yield per plant, but will not necessarily reduce fruit size. Still, to grow a big fruit, the plant will need space. Place your plants in prepared planting holes, as discussed earlier in Chapter 4, and lightly compress and level off the soil. Water the plants so as to remove any pockets of air from the soil.
Fibrous Roots vs. a Tap Root
Transplanting, the repotting of tomato plants into larger pots, breaks off the very small taproot that normally would go deep into the soil to take up moisture and nutrients. The mass of fibrous roots caused by breaking the tap root can reach out several feet before turning down – though never to the depth the original, undisturbed, tap root would have. That isn't necessarily bad if most of the nutrients and moisture in your garden are confined to the top foot or so of the soil. But, would plants have more nutrients and water available to them if they could reach further down? Are we correct in transplanting up to larger pots and then into the ground, or should we start seeds in large containers with no transplanting, so the tap root is essentially undisturbed? Maybe we should even consider directly planting our seeds in the ground.
(Based in part on a discussion on the Growing Tomatoes Forum of the GardenWeb.)
Grower Comments on Transplanting
"If you want to keep your plants inside until late May or early June, keep potting up. Half-gallon paper milk containers make a good container to handle a large plant. If you have a greenhouse, they should do fine until June. When you plant, use a piece of fencing with plastic encircling it to protect the plant from cold and wind. It will do a great job of protection. If you do this, you can plant out earlier." Minnie Z.
"Spring soil preparation begins in our garden after all other competitive vegetables are planted and on their way. First off, each tomato planting area has a hole dug out about 18 to 20 inches deep and 24 inches across. Each planting hole is right beside the next hole so the tomato plants will be about 30 inches apart – they are set in a straight line. The holes are filled with an even mixture of well composted manure, garden compost, and sandy topsoil. A small amount of household tomato food and a beneficial bacteria [mycorrhizal fungi] are also mixed in as well. A 50 foot soaker hose is set about 5 inches into the ground, and runs along the length of the planting site about 12 inches from the tomato plants. It will be used for watering later in the season. The tomatoes are planted as deep as possible with any lower leaves picked off if they will be buried. Large support stakes which are 2 x 2 inch and 6 foot in length are set in place at this time, and small bamboo sticks are used to support the plants until they can be secured to the main stake. The plants are well watered for the first two weeks with a 10-52-10 water soluble fertilizer used twice a week." Chris L
"After my soil had been prepped in the fall, I dig a small trench starting about 2 feet from the stake I have already pounded in the ground. My stakes are 8 foot, 1 by 3 inch, and I pound them in at least a foot deep or until they're solid. I figure the weight of the plant will need to be held up. My big plants often fall over late in the season, so I may change my method if I hear better ideas. I trench about 4 to 6 inches deep and 2 foot long. I pound in the stake about 2 foot away from where I start planting the root. I bury the plant sideways in the trench up to the first three leaves counting the top bud. I keep pruning and burying up to the top three leaves until I'm at the stake and then I train the vine up the stake. I believe this made a big difference in the size of my fruit this season. I put about a half gallon of 10-50-10 Peters Professional Plantfood in the trench and another half gallon of warm water in the trench before putting in the plant. I plant each plant 4 to 6 foot from one another. I mark my stakes with permanent marker with two letters to designate the type I'm planting. For example: "DL" for Delicious, "BU" for Burgess, "TC" for Thunder Creek, "BZ" for Big Zac, "PF" for Phil's Fantastic, etc. I continue to water every day or two along where the root is lengthways in the ground, and give it a good gallon over each root." Don C.
Tomato Plant Roots
If allowed to grow naturally, tomatoes have a strong taproot which can grow as long as 6 feet. But, because tomatoes are usually transplanted, the taproot is broken and the plant develops a fibrous rooting system. Most of the roots grow laterally two to ten inches beneath the soil surface. Some of the laterals can grow out two or more feet before growing downward to a depth of up to four feet.
