If you struggle with poor quality soil or simply want an instant, fuss-free raised bed I've got a fantastic low-cost solution for you: an abundant, easy-care, straw bale garden...
How Straw Bale Gardening Works
Straw is the dry, hollow stalks left from cereal crops like wheat and barley. It has so many uses, from animal bedding, basketry and hats, to thatching, construction and as a source of fuel. And then there’s gardening. It makes a great mulch, can be used to grow potatoes and mushrooms, can help keep ponds clear, and makes instant planters.
Straw bales eventually decompose like any other organic material, but because the outside edges are less insulated, they break down slower than the straw towards the center of the bale. What you end up with is essentially a largely intact shell filled with the beginnings of a compost pile – the perfect planter!
As the straw rots, it releases its nutrients, feeding the plants grown in it. Straw bales have plenty of other benefits too: they raise the planting area, meaning you need to bend less; they help reduce weeds, pests and diseases; and because of their sheer size, they dry out slower in hot weather. Genius, right?!
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Straw bales are particularly suited to growing fruiting vegetables like summer squash
Source straw bales from local farms, garden centres, some DIY stores, or try searching online. Organic bales are harder to find. If you’re using bales that haven’t been grown organically, make sure to avoid any that have been treated with persistent herbicides.
You can place your bales straight onto bare ground, grass or a hard surface like paving. Ensure the twine holding them together runs along the sides of your bale planters. The cut ends of the straw should then face up, which will make getting water down into the bales a lot easier.
Condition Your Straw Bales For Planting
Straw bale gardening may look like it’s just planting into bales but there’s an essential process you need to complete first.
Bales need conditioning before planting, which simply means starting off the composting process. For this we need two things: water, and a quick-release, high-nitrogen fertiliser such as ammonium sulphate, a soluble lawn fertiliser, or blood meal as an organic alternative. Conditioning takes about two weeks in total.
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Your straw bale will need to be charged with fertiliser before planting
Day 1
Sprinkle one cup of your high-nitrogen fertiliser over the top of each bale. Aim for a nice, even coverage. Now water it in with about a gallon (4 litres) of water. If you have time, it’s worth filling a bucket with water the day before so it can warm up to air temperature. This will help to speed things along, but don’t worry if this isn’t possible or convenient, it just means things may take a little longer.
Day 2
Soak each of your bales with another gallon of water.
Days 3-4
Repeat the process over the next four days: fertiliser and water on days three and five, just water on days four and six.
Days 7-9
Each day, add half a cup of fertiliser to your bales then water them as usual.
Day 10
Water in one cup of balanced fertiliser per bale (that’s a fertiliser with equal parts nitrogen, phosphorus and potassium).
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Keep straw bale crops well watered and fertilised
During this whole time the temperature inside the bales will increase, easily reaching in excess of 100ºF (38ºC), before gradually cooling back down. From day 11 onwards, keep the bales moist and periodically check the temperature at the top of the bale where the roots will initially be. Once it doesn’t feel overly warm, you’re good to go – usually on about day 12, but up to a week longer if you’re using organic fertilisers, which will take a bit longer to work their magic. Any sprouting grains in the bale can just be plucked out. The bale won’t really look any different, but they are indeed now conditioned, full of composting goodness and ready to plant!
Best Plants For Straw Bale Gardening
Straw bale planters are most often used for warm-season fruiting vegetables like tomatoes, cucumbers, peppers and zucchini. Start them off in pots then plant them into your bales by pulling or gouging out enough straw to accommodate the rootballs. Firm them into place so there’s good contact between the roots and straw then thoroughly water. The dug-out straw can be left on top of the bales or banked up against tomato plants as additional support.
You can grow just about anything in straw bales, from leafy greens to beans to onions. It’s probably best to avoid root crops as they can be a bit of a challenge, while corn may get a bit top-heavy. Large seeds like runner beans can simply be pushed down into the moist straw. For smaller seeds, top the bale off with an inch (3cm) of potting mix, and sow into that.
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For seed sowing, add a thin layer of potting mix to sow into
There’s plenty of space for roots to explore, but that doesn’t mean plants can be crammed in when growing in straw bales. Plant at the correct spacings to ensure enough light, airflow and room to expand. Remember to include supports for climbing plants like cucumber, keep the bales moist with regular watering and feed plants regularly.
Another benefit of straw bale gardening is that the leftovers are useful too! At the end of the season, you can break the bales up and add them to the compost heap or keep them dry to use as mulch next season.
