June gardening calendar

First week

Don't fertilize tomatoes until the first fruit has set. Too much nitrogen will cause leafy growth at the expense of flowers and fruit. Most other plants benefit from a starter fertilizer when transplanted.
If you fertilized earlier this spring, wait until Labor Day or Halloween to do it again. However, if you collect your clippings all summer long, another light application may be needed in early July.
It is too late for broadleaf weed-control products or combination weed and feeds. Summer's heat will cause the weed killer to vaporize and drift, damaging other flowers and vegetables. Total vegetation killers such as glyphosate can be used all season but will kill everything, so don't use them in your lawn or allow overspray onto desirable plants.
Fertilize bulbs and most perennial flowers now. Bulbs are forming next year's flowers inside, and perennials are actively growing and producing flowers.
Prune, transplant and up-pot houseplants, since they will be growing most vigorously now because of the longer days, higher light and higher temperatures. Move up to a pot only 1 or 2 inches larger at a time. Fertilize monthly.
Prune out and destroy webs of Eastern tent caterpillar found wrapped around branches of fruit trees including crabapples. The biological control sold as Dipel, Bactur or Thuricide is only effective while the caterpillars are still small. Soon they will move off the trees to pupate. Destroy these pale yellow, loosely constructed cocoons. In August, look for shiny brown egg masses on tree branches. Prune them out or scrape them off.
Examine honey locust and ash foliage for plant bugs. Control with insecticidal soap sprays as needed.
Preventive insect control for fruit-bearing trees should have been started at petal fall. Continue every 10 to14 days until autumn leaf drop.
Preventive treatment for apple scab and rust diseases should have been started before bloom started. For crabapples, collecting and destroying fallen leaves all season combined with proper watering and a fall fertilizer application may be all that is really necessary, since these diseases are not life-threatening.
There are many insect pests to watch for in the vegetable garden now. The flea beetle chews many small holes in the leaves of a wide range of vegetable crops, especially young transplants of the cole crops (broccoli, cauliflower, cabbage and brussels sprouts). Cover with floating row cover to exclude these tiny hopping bugs before they begin feeding. This covering can be left in place day and night since it is permeable to light and moisture. It also "breathes" so that heat does not build up underneath. Be sure to seal the lower edges with soil or stones. Allow ample room underneath for plant growth.
Covering cole crop plants with floating row cover will also exclude egg laying by the cabbage moths.
Potato leafhoppers are wedge-shaped, bright green insects that cause "hopperburn" on plant leaves beginning in early June. Spray once with carbaryl or malathion and cover the entire crop with row cover to prevent invasion.
Colorado potato beetle adults and larvae can be hand-picked to remove or sprayed with M-Trak, a biological control product. Adults are yellow-and-black-striped beetles, and the larvae are humpbacked and red. Look for them on the stem tips. They are present almost all season.
Striped and spotted cucumber beetles transmit a bacterial wilt to cucumbers, squashes and melons. Adults and eggs can be hand-picked throughout the season, or begin preventive sprays or dusts with rotenone or carbaryl as soon as seedlings emerge. Leaves of infected plants wilt only during the day, but the leaf stems remain erect. Eventually the entire plant wilts and dies.
Watch for the Mexican bean beetle, which descended on vegetable gardens a couple of years ago but has since subsided. To be on the safe side, you can cover the entire crop with floating row cover as soon as seedlings emerge. Spray with carbaryl or rotenone at the first sign of beetles or their distinctive feeding damage.
No further pruning should be done on trees or shrubs, since the new growth this stimulates will not mature sufficiently before the cold days of winter are again upon us.