How To Grow Leafy Greens Outdoors in Winter

Fresh vegetables reach premium prices in winter, so it just doesn’t make sense to stop gardening in the coldest months. Yet, so many of us down our garden tools at the end of autumn, and don’t pick them up again until spring, when produce prices begin to drop, again. This winter, why not challenge yourself to grow your own leafy greens? These tips will help you:

Sun trapper

Most vegetables require at least 4 to 6 hours of sunshine a day to thrive, and this includes herbs and salad greens. When selecting a site for a winter garden, keep a week-long winter diary which records the spots on your property which receive sun for the longest period of time. Be sure to note if shadow falls on these sunny situations at any time, and if it does, for how long it deprives the spots of direct sunlight. If your sunniest location is already occupied by a deck, don’t give up on using it as a gardening spot – you can always create a temporary winter garden on the site using containers or a removable raised bed.

Passive heating

Generally speaking, ‘passive heating’ refers to the ability of a particular material to absorb, retain, and distribute natural heat which arrives in the form of sunlight. While well-positioned winter gardens may receive plenty of sunshine during the day, plants thrive when the night temperature of soil doesn’t take a dramatic dip. We can help winter soil temperature to remain steady at night by building a garden against a heat-retaining wall (such as one built of brick, stone, or concrete), and by edging it with similar materials. (Māori practiced similar cultivation techniques when they edged their kūmara beds with rocks.) If you don’t have a heat-retaining wall to build a garden against, consider constructing a raised bed from recycled concrete bricks.

Dry soil is warm soil

One of the reasons a garden is so chilly in winter, is it is often wet and compacted. The drier and looser we can make the soil, the more it will drain, and warm up. Creating this warming environment isn’t difficult. To loosen up a winter bed, add plenty of dry twigs, crumbled dead stalks of annual flowers, fine grit (of the sort you would find in a river bed), dry leaves, pea straw, and well-made compost . While these material will help moisture drain as quickly as possible from your winter garden bed, you may even like to take the winter-proofing further by building your garden under the eves of your house, or by constructing a clear plastic roof or cloche over the site.

Select your seedlings

The success of a winter garden depends as much on the variety of plants you grow in it as it does on soil temperature and sunlight hours. Some edibles thrive in cooler winter temperatures while others will refuse to grow until the soil warms up. Depending on where you live in the country, coriander and parsley, for example, will quickly ‘bolt’ (grow tall seed stalks and flower heads instead of leafy foliage) if grown in warm seasons instead of in winter and early spring. ‘Spring cabbage’ will fail to form a heart if grown in summer, instead of winter, and some lettuces (usually those with red, or red-tinged, leaves) will do well in winter but less so in summer. When choosing seedlings for your winter garden, always ask at your local garden centre for a variety to suit the season and the outdoors (don’t simply assume because you see the seedlings for sale, they are suitable, as some are to supply gardeners who are growing in greenhouse situations where it is warmer).

Growing a winter garden is do-able, cost effective, and rewarding. Why not start planning one right now!