Today the sun is shining and it is very warm – currently 30.2C. Actually, it’s so warm that I decided to check out the records at the South Australian Bureau of Meteorology website. It turns out that today’s temperature is about 12C higher than the average for this month. This seems like a good time to talk about garden shade.
This spring and summer, we will not be growing edible plants in the shaded patch you can see above. We have been growing intensively here for the last 6 years and plan to improve the soil over the next 2 seasons by growing a green manure crop.
We recently added a few raised beds, with a total surface area of 5 square meters, in another part of the backyard. This is where we will grow all our edibles until autumn next year. I have already planted radishes, snow peas, capsicums, cherry tomatoes, silver beet, 5 varieties of lettuces, a couple of zucchinis and plenty of edible herbs.
I have also constructed a very simple, cheap, permanent shade structure over each raised beds. I started by sinking three, 60 cm long wooden dowels, with a diameter of 12.5 mm, in each side of the beds. They are about 650 mms apart. I then cut to size 19mm black irrigation tubing, to make loops. These are held in place by the wooden dowels. Finally, I tied a bamboo stake over the top of all the tubular loops to brace them, and tied the stake to each loop.
Old, light coloured sheets have been cut to size to use as shade cloth. They are cheaper and not as heavy as shop-bought shade cloth. I use plastic clamps to secure them to the loops and orientate them so as to protect the beds from the afternoon sun, while still allowing plenty of morning sun over the vegetables. Because our summer sun shines so bright, some light still filters through the sheets throughout the day.
This year South Australia had a generally dry winter with daytime temperatures generally warmer than average. The state-wide average rainfall for winter was 37% below the long-term average. August was also dry with rainfall generally very much below average for most locations – 20.8 mm or 30% of the long-term August average, on just 5 rain days. The usual August average rainfall is over 16 days. I found this information at the South Australia – Bureau of Meteorology website.
Because of all these factors, our soil is drier than average for this time of year. We are only two weeks into spring and our rain water tanks are already half empty because we started watering earlier and more frequently than usual. Shade helps to keep moisture in our heavily mulched soil, protects plant leaves and vegetables from sunburns and reduces the need to irrigate – saving both time and precious water. In South Australia, if we are to keep producing food in our summer gardens, shade structures are now indispensable.
UPDATED 16th October 2014:
On a windy day, I found that the single bamboo stake tied over the top of a the tubular frame was not sturdy enough to withstand the strong winds. I needed to add another two stakes, one on either side. This strengthens the whole structure and makes it ‘wind-proof’.