Wet, cool weather yields rare, green August

This is already the second-wettest August in Oklahoma City history, and we still have almost a week to set a record.

We also have been far cooler than normal for both day and night temperatures, so many of our color annuals and spring vegetables, as well as our lawns, trees and shrubs, have responded with new growth.

Most all of our plant materials in central Oklahoma are looking greener and happier than normal for late August. There are areas in southern Oklahoma that have missed most of these rains and are dealing with drought problems.

We have passed the planting deadlines for almost all of the tender or frost-sensitive vegetables if you are planting a fall food garden. There are many semi-hardy vegetables you still can plant and harvest this fall.

We are at the tail end of the fall planting season for cabbage, Chinese cabbage, cauliflower, collards, kale, kohlrabi, leek, onions and green peas. These should be planted in the next week, or you risk missing much of their harvest to hard freezes that follow the early frost dates.

Some semi-hardy vegetables are more cold tolerant and can be planted over the next several weeks, including garlic, mustard, radishes, rutabaga, spinach, Swiss chard and turnips. These root and leafy crops can survive colder temperatures and still produce tasty, fresh food for your dining enjoyment.

Gardeners and farmers always do best when they are thinking a growing season or two ahead. Someone has to plan, procure the needed seed, plants and supplies, plant the seeds, take care of them, allow these wonders of nature to grow and then provide the harvest.

More folks want to garden year round or to save more of their plants from year to year, or to be able to produce their own fresh vegetables and spring transplants right through the winter.

You can do some of this in a home window or by sliding glass doors or under lights in a spare room or the garage, but the best way is to build or buy a hobby greenhouse. If you have been dreaming of your own greenhouse, you have just eight to 10 weeks until our first freeze and need to get serious about making it happen.

There are many styles, sizes and types of greenhouses. The two most common home greenhouses are freestanding, where the greenhouse sets away from your home as its own structure, or attached, where either the side of the greenhouse literally leans on your home or garage, or an end wall of the greenhouse is a shared wall with your home, garage or other building.

Generally you have the best light, ventilation and cooling options with a freestanding greenhouse, but a lean-to of 6 feet to 16 feet wide may be less expensive to install because of easier access to water, gas and electric utilities.

The frames for either style can be built out of wood, aluminum or galvanized steel. The galvanized steel and aluminum frames generally will have the longest lives in our part of the country unless you upgrade to really good cedar or redwood.

There are many good options for skinning or glazing your greenhouse these days. Single or insulated glass is still popular for high light transmission and its clear beauty, but glass takes more framing support and is more expensive.

For decades we used lots of corrugated fiberglass, but that has been almost totally replaced by newer long-life plastic glazing like polycarbonate and acrylic that are available in either corrugated or energysaving twin wall panels.

Make sure to get greenhouse grades of these panels that will stay clear for 10 to 20 years and have an anti-condensate on the interior side to reduce dripping from the panels.

The least expensive but still good covering is copolymer or greenhouse plastic film. Greenhouse plastic films are available in one- or four-year grades so that you need to recover either every year or every four years. You can install two layers of the film and blow air with a small inflation fan between those layers to create a few inch thick airspace and reduce energy use by about a third.

We get the full dose of winter, summer and windy weather in Oklahoma, so you will probably want to add heating and winter ventilation for winter use of the greenhouse. For summer use of the greenhouse, you likely will need and want shade cloth, summer ventilation and even an evaporative cooling system. You can grow on the ground, but most hobby greenhouse users will add some plant benches or tables to make it easier to reach and work with their plants.

Enjoy your garden as you commune with your flowers and plants and harvest your vegetables. Spend some time planning and taking action to get ready for fall and winter in your garden or home greenhouse.

Rodd Moesel serves as president of Oklahoma Farm Bureau and was inducted into the Oklahoma Agriculture Hall of Fame. Email garden and landscape questions to rmoesel@americanplant.com.