How To Extend the Growing Season To Get the Most Out of Your Garden

If you missed How To Grow A Four-Season Garden – Part 1, please take a look at it first, as it contains important background information.

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Extending The Seasons

Whole books have been written about this subject – good books – so I don’t mean to re-write them here. Think of this as the Cliff’s Notes. But do read the books, too! You’ll find references below.

First, there are several different situations where you might want to use some season extension:

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In the Rain.

Here in Seattle, as in Northern California, rain is the most difficult part of our fall and winter. Rain is ok in the summer, when the heat helps dry up the plants after the rain, and the root temperatures stay warm enough for the plant to fend off most diseases (as long as the plants are otherwise well-nurtured and healthy). But when it begins to get cold (50-60F and below – depending on the crops), rain can become deadly. The antidote: protection from the rain!

Slugs, powdery mildew, and root rot are major problems in the rain. But by covering your crops using the season-extension techniques below, you should be able to stave off these problems. This protection is identical to the protection needed for those whose main issue is snow. (See below.)

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In the Frost.

There are different kinds of frosts. The first that come are light frosts, where the garden is beautifully covered in crystals, the frost usually happens in the early morning, and generally all but the most tender plants survive. Soon to follow (within a few days to a couple weeks) is the first hard frost. This is where leaves become crunchy and brittle, flowers drop, and you lose your summer crops. Unless you protect them!

You can extend your summer crops for a couple weeks to a couple of months, depending on where you live and how determined you are. You can do this one of two ways:

  1. You must pay attention to the weather, without fail, every night as it gets colder. And whenever the forecast is for frost, you must cover your summer crops with a blanket or frost cloth. Then if you like, you can uncover the plants in the morning. Or,
  2. You can erect a permanent structure over your crops. This protection is pretty much identical to the protection needed for those whose main issue is snow. (See below.)

Fall and winter crops, on the other hand, should do fine with some frosts. Many will become sweeter and more flavorful.

You can also extend your growing season in the late winter/early spring by using some of these season extension techniques. You may be able to start planting out at least a couple of weeks before your last frost. The first thing you’ll want to do is start your seeds indoors. (Be extremely cautious when hardening off as nightshades in particular are sensitive to shock.) When planting out, the most important things to remember here are: warm the soil not just the plant, and warm the soil before you plant.

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In the Snow.

I am admittedly less experienced with the snow, as I have lived in California for the past 10 years. But, I have a lot of book knowledge and I’ve been reading gardening blogs non-stop for the past couple years. However, I welcome any snow gardeners to include their own expertise here.

Just like frost, snow comes with cooler weather. So generally speaking, when you are protecting from snow, you are protecting from the cold. If it is wet snow, you’ll want to protect from the wet cold above all. An additional thing to consider with snow is the added weight added to any structure by the build-up of snow.

Watering in the Cold Rain, Frost, Sleet and Snow.

Basically, you’ll want to keep the soil as warm as you can, and the plants moist but not wet. Plants do not grow (much) in the winter, and the sun will evaporate the water less, so you’ll want to water only when the surface of the soil (1/2″ deep) becomes dry.

Only water your plants in the mornings, when the plants have time to warm up during the day. And be careful to not water the leaves or stems of the plants – aim for where the roots are. A rule of thumb is that the roots expand as far out as the leaves of the plant. So if the leaves are a foot wide, the roots will extend a foot wide beneath the soil.

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In The Heat.

Surprise! Yes, in many parts of the world (like in our former garden in Northern California), it is too hot in the summer to grow many things. But with a few techniques, you can conserve water and extend the season of your cold-weather crops. You may even be able to grow cold weather crops all year without bolting.

Season Extension Techniques

The type of season extension you chose will depend on many things: the extent of cold or wind your garden receives, cost, availability of materials, the size of your garden, and whether or not it snows and if it does how much (you’ll have to build a sturdy structure if it is to support much snow). My apologies for not having pictures of all these, but a quick search of Google images will find several you can take a look at.

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The classic cloche is a glass bell-shaped vessel placed over each individual crop. Here is a perfect example of what they look like and how they are used. They hold in heat and moisture, and also protect from slugs and other critters. However, you must watch that on particularly sunny days you don’t scorch your plant in the hot sun, and in particularly moist climates you must watch for mildew (squirting a bit of milk and water on the leaves might get rid of mildew). When it’s particularly hot or moist, you can prop up the cloche a tad with a stick to let a bit of heat out, or you can buy or make a cloche with an opening at the top.

There are many places to buy these, but I would encourage you to find ways of making them or repurposing other objects. Inverted glass cookie jars work very well, Katie has created them out of plastic 2 liter soda bottles, 1 gallon plastic milk bottles work as well, this site has instructions for making it out of a hanging basket, garage sales can often be the best place to find crazy items that will work well for cloches.

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Cold Frames

In Four Season Harvest, Eliot Coleman explains cold frames very well. He and his wife live in Maine, and garden year-round. According to Coleman, night temperatures can be as much as 20F warmer inside the cold frame (average is 7-10F). On a sunny or cloudy winter day, daytime temperatures will be around 10-15F warmer.

However, during the fall and spring sometimes temperatures can spike inside the cold frame, so again, heat needs to be monitored. You can prop open the cold frame with a stick, or buy or make a cold frame that automatically opens when it gets too hot.

A cold frame also protects from rain, wind, and snow. In areas where you have a lot of snow, make sure you have a cold frame with a slanted roof so the snow falls off the sides and doesn’t pile up top (see the one pictured in the “In The Snow” section above).

Making a cold frame yourself allows you to make it any side and shape you like. You can make the sides out of hay bales, scrap wood, concrete blocks, bricks… anything that will keep the heat inside. The top can be made from an old window (like the one pictured above), a found piece of glass, or one bought at a hardware store. You can also put 2 windowpanes of the same size together into an A frame, hinged at the top for easy access on both sides.

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Hoop Houses

Hoop houses, row tunnels, or row covers, are generally about 3′ wide, or the width of your rows. The length is up to you. You can use thick-gauged wire (my preference), or you can use pvc pipe, wood, branches, or anything else that will create a structure that can withstand wind (and snow, if you have it).* Each hoop should be 2-4′ apart (we found 3′ works best for us). Of course this is only a rule of thumb, for you can make a hoop house as big or small, short or long as you want.

With an armature created, you have many choices of material to go over the hoops: shade cloth (different thicknesses – we use 30% and 50%, depending on the crop), plastic tarps, burlap, frost cloth, bed sheets, etc. What is nice about shade cloth is that you can put it on your greens in the summer, to shelter them from the heat. And in the winter, you can leave them on to protect them from the cold (if you live in a fairly mild region, that is). Frost cloths and thick plastic sheeting will hold in the most heat. If you use plastic, be careful to leave a vent at each end when it is hot, so that the plants don’t cook inside.

These cloths and tarps can but put on with clothes pins, heavy duty paper clips, or clips made specifically for hoop houses. And the bottom of the cloth is secured with a large fabric staple or stake (found at a local hardware store).

*Note: We bought our wire at Bountiful Gardens, but I can’t seem to find it there anymore. Eliot Coleman recommends 6.5′ long pieces of #9 wire – you can probably find it at a good local hardware store.

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Greenhouses, High Tunnels, & Domes

If you have the space, Eliot Coleman gives explicit instructions about how to build your own movable greenhouse. You can also buy a greenhouse, which can be quite pricey (though check Craig’s List, Freecycle, and garage sales). But as Coleman says, “all you need is a minimal frame and a roof that lets in light.”

Be creative!! You can make one just as you would a cold frame, piece by piece, using found windows and other objects. You can make a high tunnel that is basically a larger version of a hoop house, with metal piping or 2x4s (instead of the hoop house’s wire or pvc pipe). You can also check out Emma’s Grow Dome (above, bottom photo) – she has detailed photos of how she build it.

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If you are in cold climes (USDA zones 3-6), you may want to combine a greenhouse with mulching or a cold frame. Anyone out there who has built a greenhouse and can offer up some additional expertise?

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Mulching can help keep moisture in the soil during the hot seasons, and away from the soil during the rainy seasons. It can keep the soil cool in the summer and warmer in the winter. A light-colored mulch will reflect more heat than it draws in, which can be great when it’s really hot. I measured last summer, and our mulched soil was 10-20F cooler than the exterior temperatures (when it’s 110F outside, that can mean life or death for a plant).

If you really want to warm up your soil before an early spring planting, use a dark-colored mulch. Commercial growers use black plastic, but you may have something more biodegradable you can find.

My favorite mulch is straw (NOT HAY, which has seeds and will grow a whole lot of hay around your garden). Straw is cheap and can be found in a local feed store. If you live in the city, you may have to drive to the farming areas outside of the city to find it.

Other good mulches are leaves (which you can collect from your neighbors), grass clippings (as long as it didn’t go to seed), and burlap. I don’t really like bark mulch, because it soaks up the moisture too much – holding in too much moisture when it rains, and soaking up too much moisture when I water. But each of us gardens in a different environment with different needs, to experiment and find out what works best for you.

When you mulch, you want to give it a good 3-4″, or it won’t keep out the cold nor keep in the moisture. Make sure you give nightshade plants (tomatoes, peppers, eggplants) extra room around the stems, as they don’t like wet stems. Trees also need a good mulch-free zone around the base. You can also try to overwinter some crops by covering them entirely with straw, if you live in a very cold climate.

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Taking Advantage of the Environment

There are several ways you can plan your plantings to take advantage of your house, garage, fences, trees, and other things. Here are just a few that come to mind:

  • Tall plants next to your more vulnerable crops will shelter them from the wind.
  • Interplanting cold-weather crops like carrots and lettuces beneath larger crops like peppers and beans will protect the cooler crops from heat.
  • Raised beds will allow for the cold air to sink into the pathways rather than under your plants. This combined with mulching saved our plants from several frosts – you can feel the temperature difference.
  • Planting in the middle or top of a hill rather than the very bottom will have the same effect.
  • A tree will hold a pocket of cold air beneath it. It will also keep out badly needed light during the winter months.
  • A white or light-colored wall will reflect heat toward your plant. This helped our meyer lemon tree thrive in a cooler climate.
  • Bricks and concrete will stay warm long after the sun goes down (but they will take longer to warm up after the sun comes up, unfortunately).
  • A roof or dark surface will draw heat into the soil or into your containers. Our rooftop tomatoes and peppers (above) produced more than those on the patio.
  • We also found that our epazote weeds kept our tomatoes warm during the frosts.
  • Whatever works!

I highly recommend taking a look at Toby Hemenway’s Guide to Home-Scale Permaculture for more ideas.

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Protecting Container Plants

When protecting container plants, you can construct a teepee made of bamboo around your plant, or line your pots in a row and use wire hoops (above). Once you have an armature like this, you can cover it in plastic, burlap, or a frost cloth. You can also wrap a blanket or frost blanket around your pots for extra protection.

If you are growing perennials – like strawberries, small fruit trees, grapes, and so on – and you’re in some of the colder hardiness zones, you may want to bring in some of your containers for the winter. Last winter, Chile successfully brought her tomato plant into a warm patio to overwinter! You can bring them into the garage if they’re dormant, like a tree. But if they’re still growing, you’ll want to put them somewhere where they get a good amount of sunlight.

When you’re ready to put out your plants in the spring, make sure to harden them off, just as you would seedlings: slowly bring them in and out, a little bit more each day, to re-acclimate them.

The same can be true for particularly hot areas. If your heat index is too hot for some of your more delicate plants, you may want to bring them into the safety of your cooler house for a while. We had to do this with our seedlings last summer.

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There are many ways of preserving food through the winter, including: root cellaring, canning, drying, freezing, and storing vegetables in the ground. I wrote about sun drying and oven drying last year, as well as water-bath canning. Also check out Chile Chews’ articles on canning and Down To Earth’s articles on preserving. And I will refer you to the books below for further information about these important ways to store food.

What To Read

I can’t stress enough how important it is to soak in information, through books, websites, local gardeners and farmers, and experience in your own garden. Talk to farmers at the farmer’s market, ask local winter gardeners what varieties they grow, get the Farmer’s Almanac for your area, read books and websites, and learn, learn learn!

Here Are A Few Of My Favorite Books:

  • Four Season Harvest, by Eliot Coleman – If you only read one book about winter gardening, read this one. Eliot Coleman and his wife live in Maine (hardiness zone 4!), and they grow vegetables year-round.
  • Growing Vegetables West of the Cascades, by Steve Solomon – If you live in a pacific northwest-type climate (rainy, cloudy, temperate, zone 6-9), I highly recommend this book. I’m still perusing it, as it’s loaded with information. Most gardening books have a mid-west climate in mind, so it’s a treat to have a book written for our region.
  • Gaia’s Garden: A Guide to Home-Scale Permaculture, by Toby Hemenway – This is a good all-around gardening book to read after you have down the basic gardening techniques. It also guides you to think about natural wind-breaks, rain and sun covers, and other ways of extending the seasons naturally.
  • Square Foot Gardening, by Mel Bartholomew – This is a book many gardeners swear by, and it has a small section on season extension.
  • Seed to Seed, by Suzanne Ashworth – Not just about seed saving, this book also gives regional instructions for planting, caring for, and harvesting various plants. It’s also a book that will get you excited about gardening!
  • The Organic Gardener’s Handbook of Insect and Disease Control, by Barbara Ellis and Fern Bradley – More than anything, this book has been useful for learning about the good bugs you should be happy to have in the garden! But also it is good for the occasional outbreak of disease.
  • Root Cellaring: Natural Cold Storage of Fruits & Vegetables, by Mike and Nancy Bubel – Everything you need to know about storing your summer, fall, and winter crops through the winter months.
  • Ball Blue Book of Preserving or Ball Complete Book of Home Preserving – How to can, freeze, and dehydrate your summer and fall crops.
  • Reader’s Digest Back To Basics – This book is a great book to have around, and includes a whole section on “Enjoying Your Harvest The Year Round.”
  • Joy of Cooking – Includes all sorts of preserving recipes.
  • Recipes From America’s Small Farms – Great basic recipes for summer, fall, winter, and spring vegetables.
  • Simply in Season – Another great book of recipes, arranged by season.

What Do You Think?

What have I missed? Do you have thoughts, questions, ideas? Please share! Are you planting a winter garden this year? Have you done it before? What tips can you share with the rest of us?

Also, anyone in snowy regions have advice for growing in the snow?