Strawberries propagate easily, producing runners that set new plants a short distance from the parent. These runners share the same genetic characteristics as the original, preserving the disease resistance and fruiting qualities that make the strain commercially valuable. Beds renewed by correctly cultivating the bed after fruiting produce successfully for four to five years.
Propagate new strawberry plants from transplanted nursery berry plants by moving the strawberry's runners to open spaces in the bed. Typical plantings space plants 18 to 30 in. apart in rows 3 to 4 ft. apart. A month or more after planting, strawberries send out runner tendrils which normally root a few inches to a foot from the mother plant. Use a trowel to relocate the new plants 3 to 4 in. apart in the row. Make the bed no more than 2 ft. wide, with plants uniformly spaced.
Prune strawberry flower clusters from first-year plants to encourage runners. If not allowed to set fruit, all the energy of the first year goes into plant growth and propagation. Cultivate or hoe empty sections of the bed weekly until new plants fill in the spaces. Loose soil encourages the strawberry runners to take root, and the frequent cultivation reduces competition from weeds.
Renew second-year beds after the strawberry harvest by mowing the bed to remove old leaves and tilling under all but a central row about 6 in. wide. Cultivate the empty space and set new runners as the center plants again fill in the bed. This method works for several seasons, but after four to five years, when harvest does decline, plow the bed under and begin a new berry patch somewhere else in the garden.
Buy disease-free nursery stock for new plantings. Although berry plants transplanted from old rows could form the basis of a new berry bed, any diseases from the old plantings travel with them. If you use an old bed as a source of new plants, prune flowers from healthy berry plants to prevent fruiting. Allow the old plants to set enough runners for a new bed and transplant the runner plants when roots and leaves develop fully. Till the old plants under.