September Gardening Topics

Winter Squash Harvesting

Winter squash is ready to pick when the stem begins to shrivel. Press the rind with your fingernail, it should resist denting. Pick before the first hard frost and cure by letting it lie in the sun for at least 3 days, turning it each day. Store in a cool, dry place. It will keep for up to 5 months. 

Brown Spots on Apples

You may have noticed small areas just under the skin that are brown and corky. The spots may even appear after harvest. This is called bitter pit and is caused by a calcium deficiency early in the spring. Bitter pit can be treated by spraying the leaves with calcium nitrate at the rate of one tablespoon per gallon of water in the spring just after bloom and again one or two months later. Mark your calendar as a reminder.

Leafcutter Bees

Do your rose bush leaves have smooth round holes in them? The likely culprit is the female leafcutter bee. The bee cuts smooth round or oval leaf fragments and uses them to line each underground brood cell that she fills with nectar and pollen. When the cell is ready, a single egg is sealed inside. The larva pupates (matures) in the chamber and emerges in the spring. The hole in the leaf is much larger than an ordinary caterpillar would make and is very smooth as if a miniature cookie cutter was used. The bee can chew off a leaf fragment in less then a minute with its sharp jaws. The leafcutter bee is considered to be a beneficial insect. And rose leaves seem to be their favorite.

Spider Mites

Spider mites are closely related to spiders and are about the size of the period on this sentence. They feed on many kinds of plants. They suck out plant juices from leaves, flowers and the blossom end of fruit. Plant leaves may become stippled with yellow and webs may be visible. Hotter temperatures and dusty conditions encourage them. Conserving natural enemies by not using pesticides, providing sufficient irrigation and reducing dust may all help control mites. Periodic washing of leaves with water can be very effective in reducing their numbers. If treatment is necessary, spider mites can be controlled with insecticidal soap, horticultural oil or neem oil. Releases of predatory mites have been used in some situations. More information is available in the UC Pest Note on Spider Mites.

Watering Trees

Even if a tree gets watered every time the lawn does, it needs deep watering twice during the summer. Use a soaker or drip hose around the tree at the drip line and let it slowly drip for 2 to 3 hours. A mature ornamental tree or street tree may not need any water. Mature fruit trees should watered by filling a watering basin around the tree every three or four weeks. Young fruit trees need watering every two weeks. Don't let lawn sprinklers hit tree trunks as this may cause crown rot and damage the tree.

Bougainvillea Pruning

You can prune at any time to shape or direct growth. If it is growing  on a wall, cut back long stems to keep producing flowering wood. Hard pruning to renew the plant should be done in the spring after last frost. Fertilize spring and summer.

Carrots

If you have a light fluffy soil, perhaps in a raised bed, you can grow those long beautiful carrots you see in the grocery store. However most of us have a heavy clay soil and it is best to grow the shorter varieties. Adding organic material such as compost rather than manure is good. The seeds are very tiny and mixing sand with them will help you not overseed. Plant no more than 1/2 inch deep. Carrots are slow to germinate and could take as long as 3 weeks. Keep the soil moist until they're up. Thin to 2 or 3 inches apart. Plant every few weeks for a continuous crop. If you have limited space, try growing in among your ornamentals, their feathery tops can look quite pretty. They can also be grown in a container. Some common problems are twisted roots from planting too close together, forked or deformed roots from clods and rocks in the soil, hairy root from too much nitrogen and splitting from too much water.

Gardenia with Yellowing Leaves

Chlorosis is usually caused by a lack of iron in the soil. With a mild case, the veins remain green and as it becomes more severe will turn completely yellow. Treat the soil with iron chelate according the package directions.

Grasscycling

Leave the clippings on the lawn when mowing. This provides nitrogen for the lawn.  Mow frequently so that no more than 1/3 of the length of the grass blade is cut in any one mowing. Grass decomposes rapidly and very little thatch is formed. Small amounts of thatch can actually be beneficial to a lawn, serving as a mulch. Many parks and golf courses have been doing this for years. Other uses for grass clippings include mulching for weed control and as a great addition to your compost pile. There are some states that no longer will allow grass clippings in their dumps. Refer to the UC Guide to Healthy Lawns for more lawn care information.

Mosaic Virus

Mosaic virus on squash and cucumber plants is a disease spread by aphids and cucumber beetles. The leaves become rough and mottled, the plant becomes stunted and the fruit can be whitish. Pull the plant and put it in the trash. Do not compost.

Neem Oil

Neem oil is an approved pesticide in California for use on ornamental and food plants. It is derived from the neem tree. Aphids, caterpillars, loopers, mealy bugs, thrips, whiteflies, and diseases like mildew and rust are effectively controlled. It is most effective when alternated with insecticidal soap or pyrethrum, killing problem insects in different stages of development. Follow label instructions. Spray 2 or 3 times from 7 to 10 days apart. As with all horticultural oils, do not spray if daytime temperatures will exceed 90F.

Roof Rats

Have you found snail empty shells stashed in out of the way places, fruit with holes gnawed in them or grape skins scattered around? This could indicate roof rats. Roof rats are agile climbers and usually live and nest in shrubs, trees, and dense ground cover like ivy. Good sanitation is required. Garbage and garden debris should be eliminated. Use tight fitting lids on garbage cans. Thin out dense vegetation to make the habitat less desirable. Mow ivy once a year to the ground. Climbing ivies on fences or buildings should be removed.

Trapping is the safest and easiest method for controlling rats. The simple snap trap is effective. The most important thing about trapping rats is to have lots of patience and keep trying. Wet some oatmeal enough for it to hold together, add dog or cat kibble or bits of lightly cooked bacon mixed in. Other baits to try are peanut butter and fresh fruit. Set traps where rats are likely to travel or where you see droppings along fence lines or building. Bait the trap but do not set it for several days. Try different baits in multiple traps until you find one the rats like. Put two traps facing each other. After the rats are accustomed to being fed, then set the traps. If the rat springs the trap but doesn't get caught, move the traps to a different place and change to different baits. Rats prefer secluded spots and will be less wary there. Be sure to secure the trap with a wire or nails. Above all be patient.

Italian Plum Tomato Drying

Clean and dry tomatoes. Peel if desired by dipping the tomato into boiling water for 10 to 15 seconds and pull off the skin with a knife. Cut in half, place cut side up on drying rack (cake racks work well) and sprinkle with salt (optional). For sun drying, cover with cheesecloth but don't let it touch the tomatoes. Dry for two or three days or until they are pliable but no longer sticky. Turn at least once a day. Take the racks in at night. For oven drying, set the temperature at the lowest setting or 150F and leave the oven door ajar. The dehydrator should be set at 125F. Dry until the tomatoes are pliable but not sticky or hard. Switch the racks around occasionally. This should take six to eight hours. Cool completely and seal in containers such as freezer bags or canning jars. They will keep in a cool dark place or freeze well.

Worm Composting

Worm composting is a convenient way to compost kitchen waste and provide compost for your vegetable garden. The Santa Clara County Home Composting Program has directions and information on how the build or obtain a low-cost bin to house the worms, where to obtain worms, what to feed them, and how to harvest the compost. Santa Clara County Home Composting website