Watermelons and cantaloupes need a long growing season with warm soil temperatures to produce well. They are not a worthwhile crop in many areas because the warm growing season is not long enough for them to do very much. Research at Virginia Tech and other state universities has shown they can start to bear fruit earlier and much of it during the season by using a black plastic mulch.
The black plastic absorbs heat during the day and inhibits loss of it during the night. Soil temperatures stay higher and permit planting about two weeks earlier in the season.
Early in the summer at Virginia Tech the benefits of the black plastic mulch became evident. The plants in the mulched plots grew much more vigorously and began running much earlier than those on bare ground. At harvest time, in the first 11 days cantaloupe yields on plastic were 5 to 15 times higher than on bare ground. Early watermelon yields were likewise increased two-to three-fold.
The effects of the mulch continued through the harvest season, with yields of all but one variety doubled on black plastic. No differences were apparent in any quality parameters such as size, appearance and flavor.
It has always been assumed that melons must be grown from transplants under southwest Virginia conditions, the research report said.
In this test, the transplants did generally produce a larger early yield but by the end of the season there was no difference in total yeilds. The early response might be increased further by direct seeding a week or two earlier, particularly under hot caps.
Compared to the standard method of melon production in Virginia (transplants on bare soil), direct seeding through black plastic yielded 2.3 times as many good fruit.
Research from many states has shown that the increased production from the use of black plastic more than compensates for the added initial costs of labor and material. This is certainly true for cooler climates and higher elevations where melons cannot be grown without it. Using transplants did not increase yields but did provide earlier fruit.
The black plastic improved soil moisture under it and also reduced competition from weeds. The weeds cannot get started without light under the black plastic. The white material reflects heat and light and allows weeds to grow beneath it.
Small holes can be punched in the plastic with an ice pick to allow for moisture penetration. Covering the plastic with half an inch of tree bark can take away the unattractive appearance of the plastic.
Black plastic also can be successful for providing an earlier crop of tomatoes. They should not be planted outdoors until the soil temperature stays at 60 degrees F. or above around the clock. Cooler temperatures have a deterrent effect on them throughout their life in the garden. By using black plastic, they can be planted outdoors earlier.
Unless the tree is kept at a reasonable height, pruning in the upper sections becomes quite a problem. Spraying in the higher portions also becomes a problem, and it is less effective in the control of disease and insect pests. It is much more difficult to harvest apples from a tall tree.
When one branch is growing directly over another, shading it, the least desirable of the two should be removed. Cut off all dead and diseased wood, all branches that have a tendency to grow inward toward the tree's center (thus shading lower branches) and all water sprouts or suckers that sometimes develop following annual pruning and where a tree has been pruned excessively.
Peaches are borne from buds or shoots that developed last year, and stimulation of new shoot growth by pruning and fertilization is important.
Remove branches that are broken or diseased, those that are slender and weak, especially on the inside of the crown, those that grow toward the center or straight up, and those that are growing downward.
Then thin out the top to let sunlight into the center of the crown and to permit more effective spraying. Branches that grow quite long without having side branches on them should be cut back in order to stinulate side brahches nearer the trunk.
The sun acts as an efficient disinfectant for wounds on fruit trees. There is no point in painting or using wound dressings. Healing occurs rapidly and generally the cut does not become infected. In fact, painting over cuts is often more harmful than leaving them open.