Growing Under Cover

The mission of Storey Publishing is to serve our customers by publishing practical information that encourages personal independence in harmony with the environment.

Edited by Carleen Madigan

Art direction by Carolyn Eckert

Book design by Carolyn Eckert and Erin Dawson

Indexed by Christine R. Lindemer, Boston Road Communications

Cover photography by © Jeff Cooke/Cooked Photography

Interior photography by © Jeff Cooke/Cooked Photography and © Niki Jabbour, 11 l., 15, 19 t., 29, 42, 48, 52, 58, 61–65, 67, 68, 74, 75, 80, 84, 94 t., 101 l., 102, 118 r., 129, 132 r., 134 t., 135, 137 t., 142 l., 147 t., 148, 151, 154, 158, 160 r., 164 t., 165 t., 167 r., 173, 176 r., 182 r., 192 l., 197, 201, 205; © Niki Jabbour, taken at Watershed Farm, 60, 123, 165 b., 182 l., 188 l.

Additional photography by © Agriology/Alamy Stock Photo, 133; © Avalon/Photoshot License/Alamy Stock Photo, 107 b.l.; © Besjunior/Alamy Stock Photo, 107 b.r.; © Brenda Franklin, 44, 89; © Clearskiesahead/iStock.com, 55 l.; © GordonImages/iStock.com, 126; © Hartley Botanic, 46, 54; © inomasa/iStock.com, 107 t.l.; © Island Images/Alamy Stock Photo, 92; © Janet Horton/Alamy Stock Photo, 105 t.l.; © jess311/iStock .com, 134 b., 137 b.; © Jessica Walliser, 121 r.; © John Glover/GAP Photos, 161; © Joseph De Sciose, 28, 37 l., 39, 41; © Kay Roxby/Alamy Stock Photo, 132 l.; © Ken Leslie/Alamy Stock Photo, 186; © Loop Images Ltd/Alamy Stock Photo, 111; © Nan Sterman, 2019, 18; © Pavel Abramov/iStock.com, 136 b.r.; © Regenerative Design Group, 70, 71; © sasimoto/stock.adobe.com, 170; © schankz/Shutterstock.com, 134 m.;© Sergey_Fedoskin/iStock.com, 107 t.r.; © Slavomira Kovacova/iStock.com, 181 m.; © slertwit/123RF.com, 131; Courtesy of Steve Farley, The Optimistic Gardener, 56; © Tara Nolan, 37 r.; © Veg Organic/Alamy Stock Photo, 147 m.; © Westend61 GmbH/Alamy Stock Photo, 171; © World History Archive/Alamy Stock Photo, 21; © y-studio/iStock.com, 55 r.

Text © 2020 by Niki Jabbour

Ebook production by Slavica A. Walzl

Ebook version 1.0

December 25. 2020

All rights reserved. No part of this book may be reproduced without written permission from the publisher, except by a reviewer who may quote brief passages or reproduce illustrations in a review with appropriate credits; nor may any part of this book be reproduced, stored in a retrieval system, or transmitted in any form or by any means — electronic, mechanical, photocopying, recording, or other — without written permission from the publisher.

The information in this book is true and complete to the best of our knowledge. All recommendations are made without guarantee on the part of the author or Storey Publishing. The author and publisher disclaim any liability in connection with the use of this information.

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Library of Congress Cataloging-in-Publication Data

Names: Jabbour, Niki, author.

Title: Growing under cover / Niki Jabbour.

Description: North Adams, MA : Storey Publishing, [2020] | Includes index.

Identifiers: LCCN 2020028928 (print) | LCCN 2020028929 (ebook) | ISBN 9781635861310 (paperback) | ISBN 9781635861327 (ebook)

Subjects: LCSH: Vegetable gardening. | Greenhouse gardening. | Cloche gardening. | Cold-frames.

Classification: LCC SB321 .J3195 2020 (print) | LCC SB321 (ebook) | DDC 635—dc23

LC record available at https://lccn.loc.gov/2020028928

LC ebook record available at https://lccn.loc.gov/2020028929

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For Dany, Alex, and Isabelle

And for all the gardeners who deal with frost, hail, wind, drought, cold, heat, insect pests, deer, groundhogs, and squirrels. This one's for you.

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Contents

Preface: Why I'm an Under Cover Gardener

Part 1: Introducing the Covered Garden

1. Choosing a Structure to Fit Your Needs

2. Starting Small: Mini Hoop Tunnels and Cold Frames

3. Larger Structures: Polytunnels, Bioshelters, and Geodesic Domes

4. Growing the Covered Garden

5. Setting Up Systems

6. Preventing Diseases, Pests, and Poor Pollination

Part 2: Vegetables That Love a Cover

Artichoke

Arugula

Beans

Beets

Broccoli & Cauliflower

Cabbage & Chinese Cabbage

Carrots

Celery & Celeriac

Cucumbers

Eggplant

Endive

Fennel

Kale & Collards

Lettuce

Melon & Watermelons

Parsnips

Peas

Peppers

Radishes & Turnips

Scallions

Spinach

Squash

Swiss Chard

Tomatoes

Acknowledgments

Metric Conversions

Index

Gather Great Gardening Advice with More Books by Niki Jabbour

Share Your Experience!

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Why I'm an Under Cover Gardener

I am an under cover gardener. And no, that doesn't mean I'm a garden spy covertly peeking through the hedge at my neighbor's veggie patch. It means I'm a gardener who uses simple but effective covers to grow more food.

My own introduction to gardening under cover began with a pop-up polytunnel. I was only 16 years old but was already starting seeds indoors, growing herbs in pots, and had taken control of the family vegetable garden. The simple structure, which was a gift from my parents, was really more of a small, clear tent, measuring just 6 by 8 feet. And boy, did I love it.

That first spring, I stuffed it full of all the seedlings I had grown on my mother's dining room table (hey, now I get why they gave me a polytunnel!). It didn't take long for me to learn that a covered structure warmed up quickly, even on cold days, and produced sturdy, stocky seedlings.

I had a lot of fun with that little polytunnel, but it was flimsy and only lasted a few years. Soon, I was off to university and it would be 7 years before I had my own garden space again. However, once I was back in the garden, I quickly rediscovered just how handy season extending garden covers could be.

In my first book, The Year-Round Vegetable Gardener, I shared some of my favorite techniques for harvesting homegrown vegetables and herbs in all seasons (including winter!). Today, I still use those methods, but I've also added new types of covers and structures to my food garden, to boost yields and grow healthier, higher-quality vegetables. I use more shade cloth in my summer garden to extend the harvest of cool season greens. I switched from PVC to metal hoops for my mini hoop tunnels because they're much stronger, and I added a 14-by-24-foot unheated polytunnel.

The tunnel offers plenty of space for year-round harvesting, but it's also become my garden sanctuary; I can escape to the veggie patch no matter the outside weather. It's almost always spring in the polytunnel. And with that in mind, we gave up a bit of growing space in the back corner of the tunnel to create a small indoor patio. It's the perfect spot to sow seeds, get some writing done, or just enjoy a cup of tea surrounded by a jungle of veggies.

That said, you don't need a big space or a huge garden to use the methods featured in this book. Many of my under cover techniques can be used in super small gardens, a single raised bed, or even containers on a deck or patio. You also don't need to spend a lot of money to become an under cover gardener. There are many inexpensive — or free! — types of covers that you can put to work in your garden.

I've learned a lot about matching covers to crops. The types of covers and structures I use depend on the season and the crops being grown. Of course, there's also a lot of overlap, as many of the covers can be used in more than one season. For instance, I use row covers in spring, summer, fall, and winter, but shade cloth is really just for summer.

Gardening under cover is not just about sheltering crops from cold or heat. It can also be a temporary fix for inclement weather like hail, downpours, or strong winds. Or a way to keep birds, deer, groundhogs, rabbits, and other pests away from your vegetables. I battle deer on a daily basis, and a simple length of netting floated on mini hoops helps give young seedlings a deer-free head start.

Covers also help keep insects like flea beetles, cabbage worms, and cucumber beetles from decimating my crops. They can even reduce the occurrence of diseases like tomato blight, which is devastating to garden-grown tomatoes; those grown in greenhouses or polytunnels are less susceptible to this common fungus.

If you're new to garden covers, this may all sound like a lot of work, but trust me — it's not. I'm not one to fuss over my plants, but using covers to extend and protect the harvest is both easy and effective. It's turned our traditional summer vegetable garden into a year-round food factory!

The garden covers featured in this book are the perfect complement to a home vegetable garden. If you're new to food gardening, there's no need to jump right into a greenhouse or polytunnel. Start with a row cover or mini hoop tunnel, graduating to a cold frame after a year or two. As you gain skills, confidence, and experience, you may discover that you're ready to tackle a small backyard dome or a DIY polytunnel.

What should you grow within these covers? Grow what you like to eat! But should you want more specific information, I've shared the growing details of a wide range of vegetables in part 2, and listed all the garden covers I use for each vegetable.

In the end, my message is simple: garden covers are the easiest way to grow more food for a longer period of time, grow higher-quality plants bothered by fewer pests and diseases, and mitigate the stresses caused by cold, heat, and extreme weather.

Eight Reasons to Become an Under Cover Gardener

Grow more food. We all want to be as efficient and grow as much food as possible in our gardens; using covers and covered structures will allow you to do just that.

Control the environment. Depending on the crop, your vegetables can be susceptible to heat, cold, wind, hail, snow, and other environmental conditions. Using covers or structures to create microclimates aids in preventing damage and maintaining crop quality.

Harvest year-round. Being able to provide homegrown food for my family 365 days a year is something that I'm proud to brag about. But the truth is that it's not that hard. Covers allow me to harvest sooner in spring, later in fall, and throughout the winter.

Save money. Like most gardeners, I'm budget minded and don't like wasting money — or food! Because growing under cover helps me increase yields and enjoy a year-round harvest, I'm shaving serious dollars off my weekly grocery budget.

Reap a hyperlocal harvest. Moving food around the world creates an incredible amount of greenhouse gas emissions. If I go to my supermarket any month of the year, there's a good chance that the plastic tub of lettuce has been shipped to my Nova Scotia grocery store from California. By growing it myself, I'm cutting the distance our food has travelled from thousands of miles to mere feet.

Reduce pest problems. I'm not going to say you won't have any pest problems (let's be realistic), but you will have fewer pest problems when you use certain covers. Insect barriers, row covers, deer fencing, deep mulching, cold frames, and polytunnels are simple covers that can prevent insect and animal pests from eating your vegetables.

Grow the world. Using season-extending covers like mini hoop tunnels and polytunnels has allowed me to grow a wide variety of global vegetables like edible gourds and cucumber melons that are normally difficult to grow in a short-season region.

DIY your way to more food. Some of the more serious structures, like geodesic domes, polytunnels, and greenhouses significantly increase the amount of food you can grow, but they can be expensive to buy. However, handy gardeners will find that they can DIY many structures using commonly found materials like lumber, PVC conduit, polycarbonate, and polyethylene.

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Part 1Introducing the Covered Garden

Garden covers such as row covers, mini hoop tunnels, and cold frames have transformed my vegetable garden. They shelter crops from weather extremes, helping mitigrate the new reality of a changing climate, as well as protect against insects, deer, rabbits, and birds. By creating microclimates in the garden, they also extend the season on both ends of the summer and help create better conditions for seed germination and for new seedlings to take root. There's not a day of the year where I'm not using some type of cover to grow better crops, whether it's the new seedlings sheltering under simple cloches, tomatoes basking in the warmth of the polytunnel, arugula thriving without flea beetles with the protection an insect barrier, or hardy winter greens awaiting harvest in the dead of winter.

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1Choosing a Structure to Fit Your Needs

Garden covers aren't just for growing into winter or protecting from frost. They can be used all year long to boost yields, protect from pests, reduce disease, establish summer sowings, and improve crop quality. I use a variety of fabrics, devices, and structures to capture heat, reduce heat, provide shade, and create a barrier against pests. Most of them, like shade cloths, row covers, and mini tunnels, are inexpensive or easily made. A few, like polytunnels and greenhouses, require a larger investment.

What Type of Protection Does Your Garden Need?

What type of structure you ultimately choose depends on what your goals are. Do you want an extra-early harvest of spring greens? Do you live in a short-season region where it's difficult to mature heat-loving vegetables like tomatoes and peppers? Or are your summers hot and dry, making it hard to establish crops for fall and winter harvesting? Maybe your garden is plagued by deer, rabbits, cabbage worms, or other garden pests. Before you invest in a cover, consider why you need it.

Protection from Weather Extremes

A protective cover is any material or device that shelters plants from weather — cold, frost, wind, snow, hard rain, and hail. Structures like cold frames or mini hoop tunnels collect and trap solar energy, creating a microclimate around the vegetables inside. They can extend the harvest by weeks or months in autumn or push up the planting season by the same time frame in early spring. They can also provide warmer growing conditions, allowing gardeners in colder regions to cultivate plants like eggplants and melons.

Best Options

• Cloches for temporary cover
• Mini hoop tunnel with row cover or plastic
• Polytunnels
• Greenhouses and geodesic domes

Defense against Pests

In my garden, thin insect barrier fabrics keep pests such as cabbage worms, Colorado potato beetles, squash bugs, and cucumber beetles from eating my crops. Combining fabrics with crop rotation is a smart way for organic gardeners to thwart these common pests, but the fabrics need to be applied and removed at the right times. Apply them in early spring as soon as the seeds or seedlings have been planted. If you wait to lay your fabrics, you risk having the newly emerged adult insects find their target plants before you cover them. In that case, you're just creating a predator-free environment for them to nibble on your veggies.

Choosing a Garden Cover
	Frost protection	Spring/Fall Microclimate	Sun Protection
Insect barrier	N	Y	Y
Row cover	Y	Y	Y
Shade cloth	N	N	Y
Cloche	Y	Y	N
Mini hoop tunnel with polyethylene cover	Y	Y	N
Cold frame	Y	Y	N
Polytunnel/Greenhouse/Dome	Y	Y	N
	Pest Prevention	Disease prevention	Winter harvesting
Insect barrier	Y	N	N
Row cover	Y	N	N
Shade cloth	N	N	N
Cloche	N	N	N
Mini hoop tunnel with polyethylene cover	Y	N	Y
Cold frame	N	N	Y
Polytunnel/Greenhouse/Dome	N	Y	Y

Floating fabric on hoops above, rather than directly on top of, the plants looks tidier and prevents bunching, which can block light. Once the fabrics are on the beds, they can be left in place until the plants begin to flower (in the case of squash and cucumbers) or until harvest (in the case of broccoli, kale, or potatoes). Keep in mind that it's also important to rotate crops each season to avoid a repeat of insect infestations, diseases, or nutrient depletion.

Lightweight fabrics also make a reliable defense against larger pests like deer, rabbits, and birds. I often drape insect barriers or bird netting over my newly seeded beans, peas, corn, and lettuce, which seem particularly tempting to the local bird population. The covers are left in place until germination. They can even speed up the germination process because they help retain heat and moisture.

Best Options

• Mini hoop tunnel with row cover, insect barrier fabric, or bird netting
• For deer, rabbits, and birds: insect barrier fabric, row cover, bird netting, chicken wire
• For insects: insect barrier fabric

Shade from the Sun

For most crops, full sun (at least 8 hours per day) is necessary for healthy growth and high production. But sometimes intense sun and heat is too much for certain crops, like cool-season salad greens. If you live in a warm climate, shade cloth is a useful tool for growing a variety of vegetables. Even in my northern garden, I use it in late spring and summer to slow the bolting of my favorite salad crops like spinach, arugula, pak choi, and lettuce.

There are different weaves of shade cloth, which block different percentages of light. Common percentages include 30 and 50 percent. Shade cloth is generally floated over a garden bed to prevent heat buildup. I float shade cloth on my hoops, because it's a quick and easy way to hang the cloth, but it can also be attached to stakes at the corners of a bed. Lengths of shade cloth often come with grommets for easy hanging, but clip-on grommets are also easily available.

Best Options

• Temporary shade from an upturned laundry basket
• Mini hoop tunnel with shade cloth
• A shade house or a lath house
• A row cover

Using Structures Strategically

Layering Structures

Layering one protective structure inside another — a mini hoop tunnel layered inside a polytunnel, for example — offers additional warmth. Garden fabrics like row covers, insect barrier, and shade cloth are perhaps the easiest covers to layer inside polytunnels, greenhouses, domes, mini hoop tunnels, and cold frames. They're inexpensive, quick to install, and easy to remove.