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How to Use Paper Mulch to Extend The Growing Season and Prolong Your Summer Harvest

If you’ve been gardening long enough, you’ve probably at least heard some grower in your circle talk about season extension.

Season extension is exactly how it sounds—it’s any technique or tool that lengthens the summer growing season. Whether you’re growing heat-loving plants in October or cool-season crops in January, season extension can help improve plant productivity, yields, and harvest quality.

In this blog post, we’ll define what crops are good candidates for season extension, discuss the benefits of this age-old practice, and identify some tools (like Planters Paper Mulch) to help with season extension.

How season extension works

Season extension operates on one of two principles: 1) protecting plants from frost and cold damage, or 2) raising soil and air temperatures to an ideal level for plant growth. The most successful season extension practices use both principles to create hardy and productive plants, regardless of outdoor weather conditions.

Gardeners call spring and autumn the “shoulder seasons” since they fall on either end of summer. Season extension practices allow annual crops that couldn’t normally be grown in the shoulder seasons to thrive, extending their life cycle and harvest window.

3 advantages of season extension

Not only does this practice improve plant productivity and yields, but …

Outside of the obvious advantage of season extension (harvesting your favorite vegetables outside of their traditional growing season), there are several additional benefits of this practice:

1. Access to locally grown, fresh food year-round

A common reason most of us garden is for food sovereignty. Solidify your independence by growing your own food not just during the summer months, but through the winter too. Plus, homegrown produce tastes so much better! (Especially in the winter, when store-bought produce is picked prematurely and shipped thousands of miles to end up in your shopping basket.)

2. More robust plants produce higher-quality yields

Season extension practices push the limits of plants, encouraging them to be stronger. Hardier plants are more tolerant of pests, disease, and environmental stressors, and will produce better-tasting and more abundant fruits.

3. Increased “winter sweetening” for cool-weather crops

Some root vegetables (like carrots, beets, and parsnips) are triggered to convert starches into sugars when they are exposed to freezing temperatures. This means that the colder these vegetables get, the sweeter they taste!

Fighting against nature’s shifting seasons is more work than going with the flow, but the results are well worth it.

7 tools & techniques for season extension

Season extension practices can be as straightforward as planting cold-tolerant and early-maturing varieties, or as intensive as installing a heated greenhouse. These are our top picks for extending the growing season:

1. Irrigation

Ever heard of watering your plants the evening before a projected frost? As odd as this advice may seem, a thorough soak could save cold-sensitive plants from a deep freeze. Moist soil is warmer than dry soil, and water is warmer than ice, and moist soil will naturally insulate plant roots and leaves from dips in temperature.

2. Mulching

Mulching is one of the simplest ways to conserve moisture and maintain soil warmth as your garden transitions from summer to fall. Between wood chips, cardboard, and grass clippings there are limitless options for mulching your vegetable garden, but not all mulches are created equally. Here are two of our favorite mulching options:

Plastic mulch is used by many growers to raise soil temperatures underneath it by a few degrees, spelling the difference in months of growing time. 

Paper mulch is just as effective at raising soil temperatures, conserving moisture, and suppressing weeds—but is a biodegradable alternative that can be tilled in or composted at the end of the year. Choose between two sizes (50 feet by 2 feet or 100 feet by 4 feet) to find the perfect mulch for your garden.

Lay a length of paper mulch down on one side of the garden bed, pulling it right up to the base of your plants. Pull another piece down the other side of the garden bed, pulling it as close to the other piece as possible. Pin the mulch down with landscape staples or weights (like cinder blocks), or by shoveling dirt around the edges.

Easy to cut and manipulate, red mulch film is the perfect season extension tool for warm-season crops like tomatoes and sweet potatoes. The red film reflects heat waves onto the plants, while simultaneously conserving moisture, suppressing weeds, and even deterring pests!

Check out this article for more of our mulching recommendations.

3. Low tunnels and row covers

Low tunnels are an easy-to-assemble season extension tool. Also called caterpillar tunnels, low tunnels are made of flexible fiberglass or metal hoops that are placed above a garden bed and covered with fabric or plastic. Cloth covers are typically used in summer and early fall due to their breathability, but plastic is a better option for late fall and early winter since the heavier material traps heat better.

Unlike mulch (which only protects plant roots), row cover encloses entire plants. Floating row cover may be suspended over the garden bed with hoops to make a low tunnel or simply draped over the plants themselves if the plants are sturdy enough. For maximum frost protection, ensure at least six inches of space in between plant foliage and row cover. When used correctly, low tunnels and row covers can add five to ten degrees of warmth!

4. Greenhouses

Perhaps the most effective season extension tool, a well-built, heated greenhouse can allow you to grow food year-round. In some climates, even an unheated greenhouse might trap enough heat to keep you in tomatoes all winter long.

There is no need to invest a lot of money in a greenhouse—one tube makes between five and seven mini-greenhouses that fit perfectly over standard tomato cages (although you can use these mini-greenhouses for just about anything). To use the Garden Greenhouse with cucumbers or pepper plants, place a tomato cage or other support around the plant to help support the plastic.

5. Cloches

Traditionally, cloches were bell-shaped glass containers placed over the top of individual plants to protect them from the cold. The modern plastic cloche is just as effective at insulating plants against dips in temperature, and at Seeds ‘n Such we carry an especially unique cloche that keeps tomato plants alive down to 24 degrees Fahrenheit!

This Season Starter is the one tool you need to start—or finish—the season. Fill the plastic tubes with water and the water will absorb heat during the day and release it at night, keeping your plants warm! Intended to encircle individual plants and can be reused for several seasons.

6. Cold frames

A cold frame is really just a box with a clear lid built around a garden bed, but the simple technology effectively creates a microclimate that allows sensitive plants to survive cold nights. You can make the lid out of corrugated greenhouse plastic, old glass windows, or any material that allows sunlight to come through. When the lid is closed, a cold frame traps heat, but you can open the lid on sunny days to vent the box.

7. Hotbeds

Essentially a compost pile with a growing medium on top, hotbeds are a cheap and effective way to keep plants alive through the winter.

To build a hot bed, you’ll need to source nitrogen-rich “green” ingredients (think food scraps) followed by “brown” material (like leaves or straw). Layer the green and brown matter in a raised bed, and top it with potting soil. As the organic matter decomposes, chemical reactions will occur, providing a natural source of heat to the plants above.

With the right tools, you can extend the life of your summer garden by weeks or even months! Some tropical plants like tomatoes, peppers, and cucumbers will keep producing up until frost, so if you can delay the onset of freezing temperatures you can easily extend your harvest. Season extension also works in reverse—allowing you to start cool-season crops even earlier in the year for a longer harvest window.

Shop our fall seeds today (and don’t forget to check out our garden gear) for all your seed-starting needs. Summer’s over, but that doesn’t mean your garden has to be. Now that you understand how to use season extension practices to your advantage, there’s no reason you can’t keep eating fresh all winter long!

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