By Peter Heffelfinger
Posted April 21, 2020
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Early May is the time to transplant tomatoes, perhaps the most wished-for home vegetable in the relatively cool Northwest.The raised beds inside my 40-foot long plastic hoop house have been warming up for several weeks. Tomatoes are a tropical vine that needs warm soil to start out as well as a minimum nighttime temperature of 50F degrees in order for the flowers to set fruit. And of course, warm daytime temps to fully ripen.
Where I garden even on the warmest days of summer the onshore wind starts to roll in every afternoon around 4 pm and the temperatures start to drop. Each evening the hoop house needs to be closed up to maintain a constant overnight warmth. Conversely, the house needs to be opened up early in the morning before it gets above 80-85 F inside, which can happen quite suddenly on a sunny morning with no wind. If it gets too hot, say above 90F, the flowers will drop off. In addition, condensation forms each night on the ceiling; the droplets need to air dry in place instead of falling on the plants and causing disease. And, for watering I let the chilly well water sit in a large tank for a few hours in order to warm up a bit. Warm soil, warm air, and slightly warm water, allows a tropical plant to grow well in the cool maritime Northwest.
What with watering, pruning and staking, and watching the temperature gauge, tomato production is a full time gardening chore. But large, ripe beefsteak tomatoes, Italian Romas for sauce, and handfuls of cherry tomatoes for eating out of hand are worth all the work.
Note on transplanting using the Trench Method:
I use 1-2 foot tall starts (pinch off any flowers that may have appeared). If you dug a 2 foot deep hole in the ground, the roots would be buried in cool soil. To keep the roots close to the warm topsoil, and to propagate additional root growth, make a lateral trench with one end 8-12 inches deep, but with a gradual slope of dirt rising at 45 degrees up to the other end. Gather a small berm of dirt at the far end, rising 1-2 inches above ground level. Add a standard organic fertilizer for vegetables, mixed into the soil at the bottom of the trench.
Trim off the lower suckers and branches, leaving intact the top three branches and the main growth bud at the top. Make a small puddle of water at the deep end, put the root ball into a small depression in the mud, lay the bare stem gently on the inclined plane, with the stem of the top 3 branches resting against the berm at the other end. Use a thin bamboo stake to gently secure the exposed top branches in a slightly vertical position. Fill in the trench and continue the berm around the entire root and stem planting area. This is the permanent watering crater.
Make sure you water consistently above where the roots are, not at the stake. Water by can or hose gently onto the soil, without splashing dirt up onto the leaves, which can transmit disease. I place the gallon plastic pots the tomatoes came in, with a few pebbles inside for stability, at the center of the crater and then water directly into the pots to avoid splashing dirt on the leaves. The water also drains out slowly into the crater instead of arriving all at once and possibly breaking through the berm. Never water from above; keep the foliage dry at all times to avoid the dreaded tomato blight.