Setting out Transplants
Moisture is first concern when setting out transplants. Soil-block plants should be watered thoroughly before being put into the ground. At first, the amount of moisture in the block is more important to the establishment of the plant than the moisture level of the surrounding soil. The moisture level of the soil block allows the plant to send out new roots into the soil. Only after the roots are established does the soil moisture become more important. Blocks should be very wet at the start and should be kept moist during the transplant operation. The carrying flats and transport rack should be shaded from the sun and shielded from drying winds.
The second concern is soil contact. The transplanted blocks must be placed lightly but firmly into the soil. Avoid air pockets and uncovered edges. If transplanting is to deliver all the benefits we've discussed, it must be done well. I recommend irrigating immediately following transplanting, and not only to provide moisture. The action of the water droplets also helps to cover any carelessness when firming the plants in. Although the wet soil block planted into the dry soil will support itself surprisingly well, it can eventually suffer from stress. Irrigation is stress insurance.
Consistent depth of setting is also important for rapid plant establishment, even growth, and uniform maturity. The soil blocks should be set to their full depth in the soil. If a corner is exposed to air, the peat in the soil blocks can dry out quickly on a hot, sunny day an set the plant back. On the smallest scale, transplant holes are made with trowel. There are a number of designs for soil-block trowels, but my preference is for what I call the "dagger" style, which has upright handle and a right-angle blade. It is jabbed into the soil and pulled back toward the operator to make a neat hole for setting the plant.
I make my own dagger-style model using a bricklayer's trowel with a 2 x 5-inch blade. I first cut off 21/4 to 21/2 inches to shorten the blade, then bend the handle down to below horizontal at about the same angle that it was above. I now have a very efficient transplant trowel for soil blocks. The same tool can be used to lift blocks from the flat, if desired.
When setting out plants, be sure to space them correctly. Accurate spacing not only makes optimum use of the land area, but also improves the efficiency of all subsequent cultivations. Straight rows of evenly spaced seedlings can be cultivated quickly, with the constant stopping and adjusting caused by out-of-place planting. The only way to assures accurate spacing is to measure. Stretching a tape or a knotted string is a perfectly reliable method (unless a strong wind is blowing), but it is also slow and tedious. A marker rake equipped with adjustable teeth for both lengthways and crossways marking is faster. A roller with teeth on it to mark all the plant sites in one trip is better yet.
The Studded Roller
For more efficient transplanting, the next idea is to combine the spacing and hole-making operations in one tool. If a marking roller is fitted with studs that are the size of the soil blocks, both jobs can be done at once. In newly tilled ground, this "studded roller" will leave a regular set of cubic holes in the soil.
A few design modifications can make this idea work even better. The marking studs should have slightly tapered sides (10 degrees) to make a more stable hole. The roller should ideally be 111/2 inches in diameter ( you should be able to get a local metalworking shop to make one for you). That gives it a rolling circumference of 36 inches. Then, if a number of stud attachment holes are drilled in the roller, plants can be spaced at 6, 12, 18, or 24-inches in the row. The roller can be make 24 inches wide, half the width of a standard planting strip, or the full 48-inch width for the growing area in the 60-inch strip, or 30 inches wide for the growing area in the 42-inch strip. After the ground is tilled, one trip down and back the 24-inch studded roller, or a single trip with the 30 or 49-inch roller, will prepare the entire strip for transplanting. The final step is simply to set the square soil block int eh square hole. When placing the soil blocks, the soil should be lightly firmed around it with the tips of the fingers.
The above is an excellent system, one that I have used myself and haveseen in operation on a number of European farms. It has just two small drawbacks. First, if the soil dries out between tilling and rolling,the holes will not form well. Second, the soil at the bottom and sides of the hole is compressed and could inhibit easy root penetration. These are minor points, but they do make a difference. One improvement is to replace the soil block maker studs with small (2 x 3-inch) trowel blades. These are attached to the roller at a 15 degree angle toward the direction of travel. The rotation of the roller causes these "shovels" to dig small holes. Since the holes are scooped rather than pressed, there is no soil-compaction problem.
The next step is to improve the efficiency of the system from two trips over the field to one by combining tilling and rolling in one operation. This is done by mounting a roller with blocks as closely as possible behind the tines of the tiller, after removing the back plate. In this way the holes are formed immediately in moist, newly tilled soil. Compaction is avoided because the roller has become the back plate of the tilling unit. The soil, driven against it by the tines, is falling back into place at the same time the soil block makers are forming the holes. The roller is attached by arms hinged to the sides of the tine cover. Metal blocks welded onto the bottom edges of the tine cover raise the roller when the tiller is lifted at the end of the row.
With this one-pass tiller/hole-maker, plus the convenience of modular plants in soil blocks, the small-scale vegetable grower now has a very efficient transplant system for all the crops in 11/2-inch and 2-inch soil blocks. The larger blocks are transplanted into holes dug by hand. A two-handed post-hole digger is the best tool for setting out 3- and 4-inch soil blocks. One quick bite of the jaws leaves a hole the perfect size.