Garden Studios

SEVERAL poor summers – and worse winters – have convinced many kitchen gardeners to bring their crops under cover

If you’re considering protected cropping, you’ve got three main options: a standard greenhouse, a walk-in polytunnel, or a chilly frame or plant house. 

General rules

It’s best to do the development through the winter, so the structure is able to use by the beginning of the growing season in early spring. Site it in good light, ideally direct sun for all or many of the day. Good, fertile, well-drained soil is what you desire if you’ll be growing crops inside the ground, or you can lay paving or gravel over the earth and use growing bags, tubs or large pots. Position the structure as regards to an out of doors tap or water butt for convenience, as you’ll be doing plenty of watering.

Traditional greenhouse

You’ll be spoiled for choice, with aluminium or timber frames in a number sizes and shapes, though most folks opt for the usual 8ftx6ft rectangle. A greenhouse is the most costly option but additionally the sturdiest, most weather-resistant and long-lasting. It’ll even be good looking enough to put within view of the home and intensely low-maintenance (though timber frames will need regular treatment with preservative).

Best for: Multiple uses, staged displays of decorative plants, plant propagation, out of season veg/salad production, summer tomatoes and peppers.

To build: First construct a base – a dwarf brick wall four to 6 inches high on concrete foundations, or a self-assembly metal base supplied by the greenhouse manufacturer. Assemble the framework at the base, guaranteeing everything is level and decide a still day to finish the glazing in a single session. Add an automated roof and side ventilators if these aren’t supplied. These, plus greenhouse accessories, are available in from specialist suppliers along with Two Wests & Elliott (www.twowests.co.uk).

Walk-in polytunnels

These are a less expensive option, although the plastic cover will need replacing after several years’ wear and tear (opt for thick-grade, UV-inhibited polythene for a maximum life span). Polytunnels are practical in preference to pretty, so they’re best for an allotment or a veg plot down the garden, where you won’t see it out of the window everyday. 

Best for: Plant propagation, out of season veg/salad production (it’s great for early potatoes, calabrese and courgettes), summer crops (especially those who love high humidity, akin to peppers, chillies, aubergines, cucumbers and melons, though tomatoes also thrive if given enough ventilation). In case your site is windy, you’d best opt for a sturdier permanent polytunnel (available in a wide variety of sizes). In a more sheltered spot, it’s good to choose the temporary type (smallish, easily assembled with a pre-fitted cover that slips over a mild metal framework).

To build: Construct a framework of ribs from metal tubes and clamps, build wooden surrounds for doors at each end, dig a nine-inch deep trench all around the outer edges. Fitting the duvet is a two-person job and will be done on a still but sunny day (the plastic will soften and stretch because it warms up). 

Starting very first thing within the morning, unroll the plastic and drape it evenly over the framework, ensuring the sides rest within the surrounding trench. Then, with one person on both sides of the structure and dealing from the centre towards the ends, stretch the plastic evenly over the ribs, then tighten and bury the perimeters within the trench, using excavated soil piled alongside. After doing the perimeters, fold “hospital corners” around the ends and stretch the plastic cover again, end to finish, before burying the back and front edges within the trench. Use wooden battens to secure the plastic around the edges of door frames, and surplus plastic to hide the doors.

Cold frame or plant house

Better looking and longer lasting than polytunnels (though much smaller than the walk-in variety), these are the mid-price option. Plant houses are more upright and typically a bit larger than cold frames, but both are simple to collect from kits and fairly easy to transport once constructed. Choose one that’s glazed with polycarbonate in place of glass (it’s lighter and safer) and placement it next to the greenhouse, you probably have one, or alongside a shed or garage.

Best for: Bringing on young plants and occasional-growing out-of-season crops equivalent to salad leaves. You may also use a chilly frame for taller crops by removing the lid in early summer.

To build: Both come as self-assembly kits. Stand a plant house on concrete paving or gravel, a chilly frame on a sand bed or well-prepared soil, depending the way you intend to apply it. But whatever option you opt for, bringing plants under cover can assist protect them throughout the winter.