With the garden ready and the trays of seedlings fully acclimated to outdoor conditions, we are ready to set them out as soon as the proper planting date has arrived. Because Big Sam grew his tender transplants like tomatoes and peppers in open trays and started hardy crops like lettuce and broccoli direct in the soil of the cold frame, he had to wait for ideal weather to set them out.
With the first overcast day, preferably with mist or light rain falling, I start setting them out. If the weather can be caught at the right moment, the whole procedure is simplified for it will not be necessary to water the plants as they are placed in the ground. If the weather continues lowery and wet for a few days afterward, there will be no need of watering the plants after they have been set out; otherwise they will have to be watered until the roots get a good start.
If you can wait for these conditions, by all means do so. But for us the procedure is simplified by the use of plug trays or soil blocks, and it is possible, even if not preferable, to transplant in less than perfect conditions. Specific information about the handling of each vegetable, its proper planting date, spacing, and any special attention required, can be found in the Crop Guides.
As we have discussed, light is absolutely essential to garden plants. But too much sun, particularly just after setting the plants is hard on transplants. When indoor-grown plants are first brought outside for the season, they aren’t prepared for the strength of the sun. Glass filters out part of the solar spectrum, and indoor plants, to compensate, develop extra layers of light-gathering cells on their leaves. Moved outdoors suddenly, they will drop a portion of their leaves to reduce the level of photosynthesis.
Wind can be just as hard on the plants as sun, and in many actual cases compounds the stress. The good transplanting days here in Vermont often accompany the passage of a front. If it is a warm front, the days immediately following will be hot and steamy; even though the sun may be swathed in haze, the high temperatures raise the level of biological activity in both plant and soil to a point where the plant’s recently disturbed roots—on which it depends for water—just can’t keep up and it goes limp, like a person suffering from heat exhaustion.
Cold fronts are even worse, because after they pass our Eastern weather turns bright and blustery even if not cold. The combination of crystal clear skies, bright sun, and strong wind really puts a strain on the plants. The sun revs up the photosynthetic engine of the plant at the same time that the combination of low humidity and strong winds literally sucks moisture from the leaves, leaving them gasping for water that the limited root structure of the transplant is ill prepared to provide. After all, the roots draw moisture from the soil by osmosis, and the amount they can provide to the leaves is limited by their surface area. Established plants draw an enormous amount of water from the soil; fully two-thirds of the rain that falls on your garden is returned to the atmosphere by transpiration by plants. While water is essential both to carry nutrients within the plant, and for photosynthesis, the vast bulk of it merely serves, by its passage through the plant, to keep the leaves upright, and only about one percent of its actually remains in the plant.
So if the weather is forecast to change to bright and sunny, or just hot and hazy, figure out a way to rig up some shade for the plants. Partial shade is obviously better than total darkness for getting them used to life outside, so if you use a basket or a box, make sure it isn’t solid. Ideally it should be about fifty-fifty shade and sun, though even something as skimpy as brush stuck into the soil around the newly set plants will help soften the sun and wind a bit. If you want to get high-tech you can lean screens together over the row or bed; though if your garden is in a windy spot like ours you’d better fasten them down somehow. A row of cinderblocks on each side of the bed, the corners of each screen resting on a block with another block on top to hold the screens down, works well. Commercial shade cloth that can be installed on lightweight hoops is the system we use now, but for a small number of plants individual protection may make more sense. If transplant day itself is sunny, wait until late afternoon to set them out; then the strength of the spring sun will be a bit less overpowering, and the plants will have overnight to adjust.
The process of setting the plants is fairly straightforward. While I use the same general techniques as my grandfather,
One thing I will do, though, if the weather isn’t cooperative at transplant time and I want to get the seedlings off to a fast start, is to “shoot” them in with a jet of water. Take a hose with a trigger grip nozzle on it out into the garden, aim the nozzle at each spot where a plant is to go, and pull the trigger for just a second. The blast of water will burrow a small hole and temporarily fill it with soupy soil; plop the seedling quickly into the hole before the water drains away; it will set the roots for you and create the closest possible bond between root and soil, which is the key to getting those disturbed roots growing again. After setting, draw some soft, dry soil from around the spot loosely over the moist area, leaving the final depth of the plant the same it was in the flat—unless it was too leggy and it is one of the crops, like tomatoes, that respond to deep planting. The same effect can be had with a watering can from which the sprinkler cap has been removed.