University of Vermont Extension 
Department of Plant and Soil Science

Summer News Article


By Dr. Leonard Perry, Extension Professor

Dr. Vern Grubinger, Extension Associate Professor
University of Vermont

July is a good month to take a vacation. But if you plan to travel, remember to cancel the newspaper, put a hold on your mail, and hire a garden sitter. If you canít find the latter, your next best course of action is to pick all the produce that is ripe or nearing maturity before you leave to ensure continued productivity. Give the garden a good soaking, mulch young plants with clean straw to conserve water, and spray as appropriate to control insect problems that become apparent before you depart.

Many garden plants could use a shot of fertilizer about now. Lightly side dress tomatoes, peppers, winter squash, and eggplants with a source of nitrogen, either a blended garden fertilizer such as 10-10-10, or an organic fertilizer such as dried blood (12-0-0).

Use about one-half cup per plant or hill, working lightly into the soil several inches away from the plants. Frequently harvested herbs such as basil, parsley, and chives may benefit from smaller, more frequent applications of fertilizer during the rest of the growing season.

To prevent nitrogen deficiency in corn, which would result in premature yellowing of leaves and smaller ears, scatter fertilizer along the row or side dress when the plants are about a foot or two high. If you grow a lot of corn, you may want to use a concentrated form of nitrogen such as ammonium nitrate (33-0-0) or urea (45-0-0). Apply about three to four pounds per thousand square feet of corn ground, preferably just before rain, or water well after application to activate fertilizer.

Protect your squash vines from the squash vine borer. These clear winged moths lay their eggs on the stems and the hatching larvae bore into the vines, causing the plant to wilt, and possibly, die. Apply the organic pesticide B.t. (Bacillus thuringiensis) every three to four days during July and early August to kill hatching larvae before they enter the stems.

You can discourage egg laying by spreading a thin layer of wood ashes or moth flakes around the plants. To excise the larvae from the stems, if B.t. doesnít do the trick, start cutting where the wilting begins. Slit the vine until you find the grub, destroy, then bury the end of the vine in the soil to encourage rooting.

In the flower garden, pinch back chrysanthemums in early July . Cut back roses to a leaf with five leaflets to produce flowers with longer stems.

You can successfully transplant daylilies this month even though many experts recommend early spring or late summer instead.  This hardy perennial adapts to a range of soil, light, and temperature conditions, so will do well in most gardens.   If digging and dividing plants, wait until after bloom.

Set the crown (where stem and root join) about one-half to one-inch below the soil surface.  Be careful not to set plants too deeply, however, as this may cause stunting and poor growth.  Cut back tops to about six to ten inches from the ground.

If Japanese beetles are attacking your perennials, annuals, or vegetable crops, you have several options for control, including hand picking, trapping, and using natural controls. Insecticides will protect most foliage and flowering plants with the exception of roses, which open too quickly. Protect your rose bushes with netting or, in periods of heavy infestation, clip off the buds and spray the foliage. Once beetle populations die down, allow the plants to flower again.

Other tips for July: put in second plantings of long-season crops such as bush beans, broccoli, cucumbers, and cabbage by mid-July; check garlic bulbs for timely harvest towards the end of July; monitor turf for chinch bugs; visit your local farmerís market.

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