24 Apr 2020

Turn a Styrofoam box from the grocers into a self-watering planter pot

It's hard to get stuck into gardening when you're renting or don't have much space to play with.

But if you put it off until you're in "the perfect home" it may never happen — and you'll miss years of learning and growing.

If your rental has a garden, and your landlord approves, plant in the ground. But if you only have a balcony or courtyard, or your landlord is not plant-friendly, there are other options.

A wicking bed is a great one, it's a self-watering planter box which also happens to be lightweight and cheap.

What's a wicking bed?

Wicking beds were invented by Queensland-based engineer Colin Austin to grow food in hot, dry climates. It's a raised garden bed that sits over a reservoir, allowing water to be drawn up by the plants as needed.

So long as there is water in the reservoir, your plants won't dry out, so they can survive forgetful gardeners and short holidays.

Most wicking beds are large and use gravel in the water reservoir to help wick up the water but Czech-born Roman Spur has adapted his to use only potting mix in a 500mmx300mm foam box — the ones usually thrown away by greengrocers or at vegetable markets.

Roman created all sorts of low-cost ways to collect rainwater, keep chickens and grow food while renting with his young family in Brisbane, but perhaps his masterpiece is a cheap, transportable, wicking bed in a Styrofoam box.

What you can grow in a wicking bed

In a 300mm-tall Styrofoam box, you'll have about 200mm of soil, which is perfect for herbs, salad greens, strawberries, garlic, onions, dwarf beans, bush tomatoes, or peas (with a growing frame).

For larger plants — or ones that need more water — Roman has experimented with double-decker wicking beds (one box of soil over one of water) that are better for root vegetables, cucumbers, zucchini, melon, pumpkin, cauliflower and broccoli. He has even created triple-decker boxes (with two boxes of soil) for small fruit trees.

Once you're familiar with how wicking beds work, you can even make them from other "disposable" items such as 10L or 20L food-grade plastic buckets, sourced from delicatessens.

How to make a wicking bed

What you'll need:

  • Tall Styrofoam box with no holes in the base, plus its lid (or a panel from another box)
  • Three 100mm lengths of 50mm-wide PVC piping
  • Knife (sharp, pointed)
  • Bamboo skewer (about 300mm)
  • Measuring tape
  • Marker pen
  • Mosquito-proof netting, thumb tacks (optional)
  • 1 longer piece of 50mm-wide PVC pipe, 5-10cm taller than the box
  • Potting mix

Method:

1.Cut the lid (or panel from other box) down until it fits snugly into the box; this acts as a subfloor separating the soil from the water.

2.The three small pieces of PVC pipe will form the subfloor's legs, so space them out so they support its full length. When you're happy with the positioning, push them gently into the polystyrene so they create a dent showing where they need to sit. Reach inside each pipe and mark the inside with the marker pen, then remove the legs and cut out the circles with the knife. You want the floor/lid to sit on the legs, so don't cut them too large and risk the legs slipping through the holes. Hang onto the circles you cut out, as you'll need them later. Next, using a sharp stick or skewer, punch a series of drainage/aeration holes in the rest of the subfloor.

3.To stop the whole planter box flooding in heavy rain, create an overflow hole at the top of the water reservoir. Measure up 100mm from the floor of the box (on the inside — the centre of a short side is a good spot) then gently cut a small hole in the wall. If you're worried about mosquitoes getting in, use thumb tacks to pin a small scrap of netting over the hole.

4.You'll use the longer pipe to fill the reservoir. Place it on one corner of the subfloor to mark out a hole for this to fit through (it's useful to have it close to the overflow hole). Cut a circle in the subfloor so the pipe fits snugly through. Use your saved circular offcut to create a round float that will fit inside this pipe and stab the skewer into the centre (but not all the way through); this acts as a water-level indicator. How it works is explained in more detail below.

5.To assemble the bed, return the three PVC pipe legs to their positions in the subfloor and put this, legs-down, in the box, then fit the filler pipe in place (place it with the most uneven end down, to help water flow more easily).

6.Fill the legs and top section with good-quality potting mix. Fill the base with water and water the potting mix before planting out.

7.Place the water-level indicator foam-circle-down in the filler pipe; you'll see the skewer drop as the water levels falls. If mosquitoes are getting past the float, put a mesh cover over the pipe with a small hole for the skewer to fit through.

Roman's tips and hints:

  • Large, thirsty plants such as zucchini and cucumber will survive in a single planter box but may be smaller and less productive
  • Ants can be a problem — some even chew through the Styrofoam box. Roman lined the base with plastic to solve this problem.
  • Plants with invasive roots, such as mint, will grow through the Styrofoam. A plastic liner helps.
  • Styrofoam will deteriorate in the sun after a while. Painting it will cure this.
  • All plastics will leach chemicals to some extent. You can weigh this up against eating shop-bought veggies that will have been sprayed, or you can try a different material, such as an old bathtub.

SOURCE : https://www.abc.net.au/life/how-to-make-a-self-watering-planter-box/11966566

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