Sad Annuals
If you’d asked me six months ago what green manure was, I would have thought it was poo from sick farm animals. Actually, it is a type of crop grown specifically for digging immediately back into the soil. It is typically a type of legume, so fixes nitrogen from the air back into the earth and increases the level of organic matter in the soil considerably. For a few bucks worth of seeds, it is a highly cost effective way of improving your soil, particularly over the cooler months when you are happy to rest your beds.
In the front of the house we had a bed of potted colour annuals that had come to the end of their season. They were looking drab and needed replacing, so I pulled them out over the weekend. I now had a large empty bed with terrible soil – appalling drainage due to a layer of clay and very little organic matter. When I water it the water collects in puddles on the surface, yet when I dig just below the surface it is completely dry. It is actually tempting to treat it with a wetting agent, but I’d prefer to steer away from the chemicals.
Empty annual bed - notice my tragic kaffir Lime
I need to increase the organic matter in this bed to solve the problem, but it is large, and I didn’t really want to spend $100 on animal manure. My solution to this problem is green manure.
The CSIRO have developed a green manure mix called Clever Clover. It is a mix of legumes that grow through the autumn and winter, then die down in the spring, just in time for planting summer crops. Absolutely perfect for this bed, which is destined to be a pumpkin patch 🙂
The instructions specify planting in rows, but I prefer the simplified ‘scatter randomly’ method. This way, I actually only plant 3 of the 4 types of seeds in the Clever Clover mix. The mix also includes lucerne, which you can grow separately for use as mulch.
CSIRO Clever Clover
So I scattered the seeds randomly over the bed and raked them in and watered well. Hopefully they will grow well and I’ll be ready to hoe them in by springtime.
Clover Seeds
500m2 in Sydney 
I buy a cheap bag of birdseed from the supermarket, and sow that for green manure. I know it doesn’t have the nitrogen-fixing qualities of Clever Clover, but it gives you heaps of biomass that is pretty easy to dig into the soil. It also loosens the soil up nicely. Scatterings of chook poo while digging the bed over sorts the nitrogen problem.
Oh, and it really helps to sharpen your shovel before digging the green manure in!
And certainly a lot cheaper than the clever clover.