Q. When can I put tomato plants outside in the garden?
A. This has been a crazy Spring! Tomato plants grow best when soils are warm and air temperatures are above 60° F and below 90°. Traditionally, our last freeze is after mid-March. Most gardeners like to get their tomato plants out earlier than this, any time after mid-February, if its warm enough.
|Tomato stem rot occurs on tomato plants frequently when soil temperatures are cold and tomatoes are put outside too early.|
Start watching weather projections, up to a few weeks ahead, around mid-February. As soon as weather projections predict warm weather for a 2 to 3 week period after mid-February, put transplants outside and help them to adjust from the protected greenhouse to the harsher garden environment.
Put transplants in a location protected from strong wind and intense afternoon sunlight. They should get eight hours of sun every day to remain vigorous. Never plant them in the same spot in the garden year after year. Plant them in a different part of the garden each year to reduce disease problems.
Prepare the garden soil for planting while transplants acclimate. Remember, tomatoes like warm soils so garden preparation should focus on “fluffing” the soil so that it warms more quickly. Add compost to it and double dig, spade or till the soil to open it and let warm air and sunlight raise its temperature.
Heavy, wet soils warm slowly when temperatures are rising. Alternatively, cover these spots with clear plastic, if you have to, to trap heat and warm it more quickly. Pin the edges of the clear plastic to the soil to keep the heat trapped under it.When weather projections are positive, plant tomatoes transplants into warm soil along with a pre-plant fertilizer to improve rooting. If a generous application of compost was used during garden preparation, then add only a phosphorus fertilizer to the soil surrounding the transplant. This phosphorus fertilizer could be a mineral type such as triple super phosphate or a natural phosphorus source like bone meal.
|A potentially better technique is to warm the soil first with clear plastic and plant tomato seed directly into trenches in the warmed soil. This can be done in the middle of winter. This was demonstrated at the University Orchard in North Las Vegas.|