Raised garden beds – pros and cons
I’ve got several pre-fabricated raised beds in my garden – the ‘tank’ type – and having used them for a few years, have got an idea of the good and bad points of this type of gardening. Here they are!
Saves your back: A 70 cm high raised bed brings the growing medium’s surface to a comfortable height. Little or no bending required!
Neat and contained: You can focus on one relatively small area, pack it full of veges and herbs and revel in your beautiful garden while all around may be chaos. The beds are easy to mow around.
Easy to cover: If a net is needed to keep fruit fly, other insects or birds out, it’s fairly straightforward to throw over the bed or over a frame.
It takes many barrow loads to fill the deeper beds and then, because the growing medium is usually compost, mulch etc, the level drops rapidly and needs frequent topping up. I’ve heard of people putting wrapped bales of mulch in the bottom of the beds to minimise the quantity of fill needed. Palm fronds or other material that breaks down slowly can also be used.
Soil structure – when my garden beds were newly filled, seedlings didn’t take off as well as I’d hoped. One possible cause of this was that the growing medium wasn’t dense enough – the roots didn’t have enough contact with the soil, so didn’t thrive. Water also drained too freely and quickly. A solution, especially in the early days of the raised bed, is to add some topsoil to the mix. Water saving crystals could also help.
Some veges work really well in raised beds, some don’t. Sweet potatoes did well in a round, 40 cm high bed and were easy to dig out. Peas, beans and tomatoes have grown well as have parsley, lettuce, silverbeet, rocket, broccoli, marigolds and basil.
Potatoes: I planted the Green Harvest ‘Potato Salad Sensation’ mix – Cranberry Red, Sapphire and Kipfler – in the 70 cm high bed. They thrived and I congratulated myself until I realised that potatoes had to be DUG OUT. I’m glad no-one saw me using the stepladder to climb into the bed to do the harvesting!
Zucchinis: they did pretty well but in humid weather, the reduced airflow in the beds may have contributed to the powdery mildew problem. Also, as I have netted the beds to protect from insects, chooks and brush turkeys, the cucurbit family (cucumber, squash, zucchini, etc) had to be hand pollinated to ensure fruitset.
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