The easy way to grow fruit and vegetables in sacks

Summer is upon us and the garden, finally, becomes a place of refuge, warmth and burgeoning plants.

If statistics are to be believed, the green-fingered army of gardeners has expanded dramatically since lockdown struck – at least one heart-warming development of this past year.

But with great aspiration comes tribulation and for many who seek a new plant-filled life, one thing above all else presents a problem: space. Whether your precious patch is a balcony, tiny courtyard or postage-stamp patio, the challenge is not insurmountable. The key, I believe, is coffee.

Not drinking it – although that certainly helps before some digging – but the sacks it’s shipped in from the balmy tropics to our baristas and bistros. Coffee sacks are made from hessian or jute and are the perfect material, shape and size to upcycle as the space-saving dynamo that is the sack garden.

Sack gardens are the saviours of the space-deficient. They are, as the name suggests, a garden in a sack: soil replaces coffee beans and plants grow in the soil. From a lifeless concrete balcony or soulless stone patio, a garden can spring forth and the journey up the garden path can begin.

Many will understand the need for pots in a garden of no soil, but there are two reasons why the sack trumps the pot. First, the typical sack is like a tower reaching around one metre in height; plants can grow not only on top but around its sides, increasing its surface area for planting dramatically. Second, the entire garden is compostable: no plastic, no waste; at summer’s end all can go to the brown bin or compost pile.

So, with space no longer a barrier to our gardening adventures, and our ecological hat justly feathered, there’s only one thing left to do – make one.

Find your sack

To begin, you must find a sack, and as is usually the case these days, the best place to start is online. eBay has thousands and they are ridiculously cheap, around £1-1.50 each, so it’s not just space you are saving on. Or you could buy a new sack (traditionally sold as potatoes or vegetable sacks) but they are slightly more expensive, and don’t have the funky stencilled logos that reclaimed bags do.

Once you have a sack, you now need soil. The sack will take a hefty amount of soil – at least two barrows full – so finding enough soil is essential. If you have compost and surplus soil, this is perfect, but if you don’t, you’ll need to buy some. Make sure this is peat-free and buy half as much soil to compost and also add a bag of grit sand or horticultural grit. Then, if you have any rocks or gravel, add this to the bottom of the bag for stability.

Mix the soil, compost and grit together and begin filling up the bag. Fill the sack as evenly as possible, like packing a rucksack, filling every space. The bag will begin to hold its shape once it fills up and stand firm with no support. However, if it can be supported in any way – stakes, a wall or railing – this is a good insurance policy.

As mentioned, a sack garden allows planting throughout its surface so cut some planting holes around the bag from top to bottom. However, don’t get too greedy – a few holes will suffice while maintaining the integrity of the bag. Without support I would only make 6-8 holes, but with support you can get away with more.

With the bag now full to the brim with soil and holes cut and ready, the fun part can begin – plants! The sack garden can be planted with anything within reason, but I’ve found it helps to group plants together and stick to one theme. I’ve devised three separate groups for you to try with five species in each: for those who love scent and flavour there are herbs; for the foodie, fruit and vegetables; and for wildlife-lovers, wildflowers.

Herbs

For herbs, I would stick to the more compact and annual species such as basil, coriander, parsley and chives, with only one of the more perennial or shrubby varieties such oregano or rosemary. The sack doesn’t lend itself to seeding directly within so I suggest picking up these plants in plug form from your local garden centre or online (see plant list, below). Or, grow the seed separately and then plant the seedlings in the sack at a later date.

Don’t worry about different varieties of herbs, just keep it basic and you’ll be fine. Herbs love heat, light and drainage so add a little extra grit when you’re planting and make sure the bag sits in plenty of sunshine.

Edible sacks

With fruit and veg, varieties will be a little more important but, again, don’t worry overly, as the species I recommend: tomatoes, carrots, beetroots, radishes and strawberries, are all, in the main, compact by nature.

However, look out for compact tomato varieties such as ‘Rio Grande’ or ‘Tumbling Tom’. Indeed it is a useful tip in general to look for anything labelled “patio” or “dwarf”, as this differentiates one variety from another that may get too big.

Carrots such as ‘Paris Market Round’ and beetroots such as ‘Boltardy’ are globe varieties, so slightly smaller and worth seeking out. With strawberries, look for plants that appear healthy and have bountiful flowers or buds. Radishes don’t vary much, so again, just pick healthy-looking plants.

When planting up, make sure the tomato sits in the middle of the bag at the top and keep the strawberries to the sides.

Wildflowers

Finally, the wistful wildflowers to blow the blues away and bring bees and butterflies in. Surprisingly, our indigenous species can be hard to find as plants, but either order them online as plug plants or, if this fails, just choose a collection that states they’re good for pollinators.

If you can find them, I would highly recommend species such as bird’s-foot trefoil, betony, devil’s bit scabious, meadow cranesbill, and salad burnet – even if only to reel off those fabulous folkloric names.

They will flower throughout summer and into autumn, luring in pollinators and insect life, and help to keep the balance between ourselves and the natural world on an even keel.

Whichever plants you choose, don’t forget to water them in – rainwater if you can – and look to water them well (until you see water coming from the bottom of the bag) once a week or if the soil looks, and feels, overly dry.

I don’t think feeding is necessary as fresh compost will provide plenty of nutrition anyway but, if you feel inclined, try making a nettle or borage tea and applying it weekly.

The only thing left to do is revel in your new garden: watch as plants expand and grow, providing fruit, flowers and flavour all summer long – the gifts for your earlier efforts.

The secret to the sack garden, and all gardening, is to dare to fail. Someone once said 80 per cent of success is showing up. Well, summer’s here, so now is the time to take the plunge, no matter how small your space.

Plants to get you started

Fill your sack garden with a collection of small plants.

⇢ Herbs

Chef’s Complete Kitchen Herb Collection, £24.95, nine plants in 9cm pots: French tarragon, chives, lemon thyme, mint, purple sage, Greek oregano, common thyme, curled parsley (available from DT Brown Seeds).

⇢ Edibles

Mix and match veg from a specialist supplier to suit your space and tastes. Try rootsplants.co.uk for organic plugs or primrose.co.uk, which is currently offering discounts and free delivery on orders of eight or more veg plugs.

⇢ Wild flowers

Bulk-buy 50 plugs from wildflower.co.uk for £65 and share with friends (mixes include collections for bees, hedgerow, butterflies etc). Or choose plants individually from £1.15 per plug (10 plugs minimum) from Cumbria Wildflowers.