It's August and blazing hot, and your kids may be more interested in the local swimming hole than they are in the garden. But in just a few weeks, autumn temperatures will bring relief and, for some folks, an end to the growing season. The cooler weather also means fewer ripe vegetables to pick each day, and you and your child or grandchild may want to protect a few favorite plants to extend your fresh harvests as long as possible. And often there's a tangible bonus to extending the season -- nurse your plants through a few chilly nights, and you may be rewarded by a glorious period of Indian summer that keeps the veggie harvest coming in.
The changing seasons offer a great teaching opportunity. Spend some time with your child talking about day length, sunlight, and temperature and how these affect plant growth at different times of year. This is also a good time to start a late crop of cool-season vegetables. Children may be amazed to learn that even in cold climates, you can plant some vegetables in late summer and reap tasty rewards in October. Here are some planting ideas and techniques to help you extend the growing season.
Planting vegetables in containers offers considerable late-season flexibility. Shorter days and a lower angle of sunlight mean more shadows on your deck or patio. Movable containers let you reposition the pots so your plants get the most sun. If existing container plants are struggling in late summer, consider removing them and replanting with fast-growing, cool-season vegetables, such as lettuce, spinach, radishes, and kale. When cold weather arrives, container gardens are easy to protect with plastic tarps or sheets. If a hard frost threatens, you can move containers of vegetables you care about to very protected locations, or even indoors.
Protecting prized plants
If you've grown a delicious cherry tomato or a special basil with your kids, you'll want to protect this precious plant for as long as possible. You can use a number of readily available household materials to cover individual plants: plastic sheets, old blankets, towels, and even baskets. When covering a large plant like a tomato, use stakes to erect a 'tent' frame that keeps the covering material from touching the plant's foliage. Cold temperatures can damage any leaves that come in direct contact with the material.
My favorite material for protecting plants and extending the season is floating row cover. This lightweight, cheesecloth-like, white fabric lets in oxygen, water, and sunshine, but keeps the air around plants above freezing, even when temperatures dip into the low 20s (F). It's a great material for protecting young crops or smaller plants like peppers, and it can give you a jump on spring gardens, too! Floating row cover is available at garden centers, nurseries, and some mailorder catalogs.
Kids love projects, and building a simple cold frame is an ideal one for this time of year. Essentially, a cold frame is a miniature greenhouse that protects plants from chilling winds and low temperatures. Some cold frames are constructed with plastic or nylon sheeting held aloft on wire hoops or wooden frames; others are made from rigid polycarbonate or even glass. As the sun passes through the clear or translucent covering, it warms the air and ground inside the cold frame. Some of this warmth is retained overnight when the outside temperature drops. You can add to your cold frame's heat-storage capacity by placing dark-colored plastic jugs filled with water in the unit. The sun warms the water in the jugs during the day and the heat radiates out at night to help keep nearby plants warm.
If you have an old window and some planks or scrap lumber, you can build a simple cold frame. Nail the scrap wood together to form a four-sided base and top it with the storm window. Adjust the height of the sides according to the crops you want to grow in it. If you hinge the window to the wood frame at the back you can easily prop open the window on warm days to regulate heat. On cold nights, close the window and cover it with an old blanket. For a more refined structure, build the base so the front is lower than the back and the sides are angled between the two heights. Again, hinge the window to the wood frame at the back. An angled cold frame maximizes the sun your plants receive.
Ideally, locate the completed cold frame on a south-facing slope backed by a building that will protect the frame from cold north and west winds. Seed the cold frame with cool-season vegetables. Depending on where you live, your cold frame will let you harvest spinach, mache, and kale right into winter!