How to Grow a Thicker-Rooted Tomato Plant From Seed

Starting Seeds

• 1

  Purchase tomato seeds for the kinds of fruit you wish to grow. This will be based on length of growing season, disease resistance and growth habit, as well as on whether the plant has determinate or indeterminate growth -- that is, limited or unlimited growth.

• 2

  Fill a nursery flat with sterile soilless potting mix to within 1/2 an inch from the top of the flat. Sow seeds according to package directions when the last frost date for your area is six to eight weeks away.

• 3

  Water thoroughly until the potting mix is evenly wet and water is coming through the drainage holes. Place the flat in a south-facing window or under grow lights set for a minimum of 14 hours of light a day.

Transplanting

• 4

  Watch the flat for sprouting seeds. Prick out seedlings once they have two sets of true leaves above the seed leaves, or cotyledons. Put each seedling in a 2-inch pot.

• 5

  Transfer the seedlings into 4-inch pots when they have filled out the 2-inch pot. Put them into 6-inch pots when they have grown into the 4-inch pots, since frequent transplanting prunes the tap root and encourages lateral branching of side roots to develop thicker root systems. Plant the seedlings deeper into the soil at each transplanting so more roots can grow from the buried stem.

• 6

  Put the potted plants outside for several hours during the warmest part of the day to get them used to garden conditions. Continue this hardening off for a week to 10 days, lengthening the time that the plants are exposed outside each day.

Planting in the Garden

• 7

  Dig a hole if the plant is stocky or a trench if the plant has a long stem. Fit the plant temporarily in the hole or trench to make sure it is big enough to fit not only the root ball but also most of the stalk.

• 8

  Put some organic fertilizer, such as bone meal or blood meal, in the bottom of the hole or trench and work it into the soil, or use aged compost.

• 9

  Place the tomato plant in the hole so that only the top two or three sets of leaves will be above the soil. Pinch off the lower leaves that will be buried. Lay the plant on its side if using a trench so that only the top two or three sets of leaves are above ground; remove the lower leaves.

• 10

  Fill the hole or trench with well-cultivated soil without clods. Firm the soil around the root ball and around the buried stem so that roots will form all along the stem, making a thicker root system.

• 11

  Put in a wooden stake of a height to suit the mature dimension of your tomato plant. Another option is to place a tomato cage around the plant, so the root system won't be damaged by putting it in later. Water the plant immediately. Put mulch around the plant to keep the roots from drying out.