Bottle garden

In a city, one doesn’t always have access to a vegetable patch. But vertical gardens are a great way to grow food on hot, sunny walls.

Here is a 4min video of how to make this fully functional drip-irrigated vertical vegetable garden using recycled 2L plastic milk bottles.

On the Internet there are many different ideas and designs for vertical bottle gardens. Some of them are quite complicated, and need lots of hardware. My aim is always to spend as little time, money and energy as possible, and to recycle junk that is lying around anyway. Plus it must actually work. Tried and tested.

I started experimenting back in 2019. The first design was a flop. Ok I managed to grow a crop of veggies, but (a) each bottle had to be watered individually (groan!), (b) the water simply dripped out the bottom (leeching the soil), (c) the soil shrank in the bottle as it dried leaving a gap, so the water would just run around the soil without getting absorbed, (d) … anyway, there were other drawbacks that are not worth listing.

This arrangement was ultimately not successful.

The only part that really worked was the idea to use wire and square metal brackets hung loosely over the top of the wall, to hold up the bottle racks, instead of drilling and screwing anything permanently into the bricks. This system was quick and easy to put up, move and importantly – remove. On house walls one could hold up the rack by wires attached to roof rafters or window sills.

As for the bottles – after much head-scratching and fiddling, I came up with a much better system: a row of bottles, connected to each other and set up at an angle, like so:

The end bottle is the reservoir. Simply fill up this tank with water. The lid has holes punched in it. The water gently irrigates the first bottle, then dribbles slowly from one bottle to the next. Reduce the flow from the tank by blocking some of the holes with toothpicks.

A container at the bottom collects the overflow – a nutrient-rich tea, which can be poured back in the top, to recycle nutrients.

Watering is quick and easy, but the actual irrigation is slow, and the soil gets a thorough soaking. As a result it stays wet longer. You can even control the moisture level: the steeper the angle of the rack, the better it drains. If you lower the rack, more water pools in each bottle. This helps fully grown plants to cope in the heat of summer. (But avoid water logging.)

I have successfully grown several crops of vegetables: lettuce, spinach, various herbs (parsley, dill, chives, leeks, basil), celery, also green beans, radish. Even cauliflower – though the monkeys got to them first.

Cucumbers also grow very well in bottles: set up two racks about 2m apart, and zig-zag a string between them. This works for runner beans too. Just help each plant to find the right path.

Soil quality is something I am still learning about. Diluted urine, bone meal, wood ash and Epsom salt are organic alternatives to artificial fertilizer. But I have found it is easy to overfertilize, because nutrients cycle around this self-contained unit. It is probably best to replace the soil once a year, mixing in fresh compost, and rotating crops. The plastic bottles also become brittle from the sun and don’t last longer than two seasons.

On 1 November is World Vegan Day. We are not vegans, but I respect the choice. This blog is my salute to you, Douglas, Glenda, Shannon, Chloe and others. I share your love for veggies.

by Marlies Craig