September has arrived, the kids are back in school, and the vegetable garden is still producing. Wise gardeners are not only harvesting, but still planting.

Now is an ideal time to plant lettuce. Leaf lettuces, such as black seeded Simpson, Simpson Elite, and Grand Rapids, mature in 40 to 45 days. If seeded soon, they will yield a good crop before frost. It will be free from bitterness that develops during the hot days of summer.

Spinach grown in the fall is superior to that grown in the spring. Varieties with maturity dates of 45 to 50 days are Melody and Blooms Dale. Spinach thrives in the cool weather and may winter over if planted in a protected area. It will produce again in the spring.

There is still time to get two or three crops of radishes before frost. All varieties of radishes take 20 to 25 days to harvest. If seeded at two-week intervals, you may be able to harvest three crops.

Mustard greens can also be planted in September. Savanna is a hybrid that is ready to eat in 35 days.

September should be the best month for harvesting peppers. Peppers that ripen in September are from flowers that opened in August. Peppers usually do not yield well in August because the flowers are formed in July, the hottest month of the year. Peppers will not set fruit if it is too hot or too cood. This could be a poor harvest year for peppers because both July and August had unusually high temperatures.

The hot summer has been ideal weather for cantaloupe. The flavor of the fruit is controlled by the amount of sunlight and temperature. When grown in hot sunny weather, the fruit is sweet and when grown in cool, rainy weather, they lack flavor. Cantaloupes will bear until frost if the tiny fruit just beginning to form and the blossoms are removed now.

Brussels sprouts will be ready to pick late in the month of September. For the sweetest flavor, wait until they are hit by a frost. They can be harvested until the ground freezes.

Butternut and other winter squash are intended for long periods of storage, but if picked in the wrong way, will only last a short time. Never pull the fruit from the vine or break the stem off where it joins the fruit. This will leave the squash open to disease and rot. Instead, cut the stem about 1 inch from the fruit.

Most gardeners have ripe tomatoes until the plants are killed by frost. If we have an early frost predicted, pick all ripe and green fruit the night before and store in covered containers. Picked fruit should not be placed on a sunny windowsill to ripen. Green tomatoes shrivel and become pink and bitter-tasting in the sun. Place an apple with the tomatoes and store the container in a cool place. The apple produces ethylene gas, which is used by the tomato in the ripening process. The slowly ripening tomatoes don't have quite the flavor of vine-ripened fruit, but they are better than those available at the supermarket.

Pete Hale of Sarver is a Master Gardener with the Penn State Master Gardener program.