Extending the Growing Season

Extending Your Growing Season

Many gardeners start their garden around the second week in May and end harvesting the first week in September. There are methods that can be used to extend your season so that you can have fresh vegetables almost all year long. Below are a few ways that some gardeners make this happen.

The Hoop or Plastic Tunnel


This is the Cadillac of the season extending methods. Using 10 foot lengths of 1/2 inch diameter, schedule #40 white PVC pipe you can construct tunnels 3 to 4 feet wide and any length that you choose. The top is covered with corrugated clear, U.V. treated poly-carbonate. The side curtains are made from 6 mil U.V. treated (ultra violet treated) clear plastic sheeting. This is not big box hardware store plastic (it will tear quickly in the wind). You can purchase this U.V. treated plastic at many garden shops around town.

What vegetables grow better under plastic tunnels? Tomatoes, cucumbers and peppers all seem to thrive. Remember that you need to open the ends and roll up the plastic a bit on warm days. On cold nights roll it down and secure the ends.

One Gallon Milk Jugs


One of the next best methods to start your plants off early is the milk jug cloche. Save those translucent plastic one gallon milk jugs. Just cut out the bottoms and place over your plants. Keep the tops screwed on during cold weather and take them off during warm times.

Many gardeners use this method starting the first week in May for broccoli, cabbage, cauliflower and some lettuces. Not only does this keep them a bit warmer until the temperatures stabilize but it also helps prevent wind damage to the tender transplants. If you don’t use the plastic tunnel method for your peppers and cucumbers be sure to use this one. Remove about the first week in June.

Cold Frames


The use of cold frames can be very helpful. Many salvage stores have old windows that can be purchased for very cheap or you can sometime find free windows on craigslist. Make sure to check the Re-Store too. First buy your windows then construct the box around it. Notice that the back of the box is taller than the front. Close the lid on cold nights and open it up ( a little or a lot) depending on the weather. For almost unbreakable clear tops (and especially if you have children around) we recommend using clear poly-carbonate in place of glass (see picture above).

Many greens such as lettuce mixes, mustard, kale and spinach can be planted out in mid April. You will be harvesting fresh salads in the middle of May. Plant a lettuce mix and spinach in your cold frame in the middle of August. It will extend your fall planting so that you can harvest greens well into the late fall.

What is a hot bed? This is a cold frame set up that stays warm due to rotting, fresh manure under the soil.

Dig out 2 1/2 to 3 feet of the soil in your cold frame and set it aside. Now get the freshest horse or cow manure that you can find. It has to be fresh. Place a one foot layer of this manure in the bottom of your dug out cold frame. Add enough soil back on top of this manure so that it is the same height as when you started. A minimum of 1 1/2 feet of soil on top of the manure is needed. Now plant right in the soil. Lettuce mixes and spinach can be planted the first week in April with this method. In about a 6 weeks the manure is done generating heat as it ferments and your hot bed is now a cold frame again (but with very rich soil down under!).

The raised bed constructed next to a south facing brick wall of a house is an excellent way to get early tomatoes, peppers or even cucumbers. It will be the first garden bed to warm up and the last one to be hit hard by late frost.

Clear Plastic and Sheet Mulch

Clear plastic can be used to warm up the soil prior to planting beans or corn or perhaps just about any vegetable. Secure the plastic down. Bricks work great or just cover the edges of the plastic with about 4 inches of soil all around. Remove the plastic just before planting. Some gardeners apply the plastic the first week in May and remove the plastic the third week in May and plant beans or corn.

Do not keep the plastic (whether it is clear or black) down all season. The ground needs to breathe and this method does not allow this to happen.

The use of organic mulches is very worthwhile. Mulch keeps the soil moist and cooler and reduces watering. Use mulch early in the season around plants that grow in cool weather such as lettuce, spinach, broccoli, cabbage, kale, mustards and garlic to name a few. Never mulch your tomatoes, peppers, cucumbers or melons too early in the season. The end of June is not too late to wait on these. They need warm soil to grow! If you have a soil thermometer, use it. Around 10AM move the mulch away from your tomato plant. Check the temperature of the soil at a depth of 4-6 inches. If it is in the high 50’s or low 60’s then it is too cool! Remove the mulch so that the ground can warm up more. Maybe replace it in mid or late July.

What is the best mulch? Dried grass clippings free of herbicides work great and it is usually available. Clean straw is also very good. You will get a few grassy looking oat plants sprouting but these are easy to pull. Dried tree leaves also do a good job. Avoid wood mulches, saw dust, wood ashes or fresh manures around your plants.

How much mulch should you use? The rule of thumb is don’t cover your plants. Let them “see” the sun. A mulch applied 4 inches deep around the base of your plants is usually sufficient.

Do you want carrots in December? You can if you heavily mulch after the first hard frost in the fall (usually around the end of September). Cover your carrots with about 12 to 18 inches of dried tree leaves/straw mix. Make sure you extend your mulch 12 inches beyond the sides of each row. When you want a fresh carrot just pull back the mulch and dig one out. It will be the sweetest carrot you ever tasted. Try this method on beets, spinach and parsnips too.

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