How to grow an edible garden - part two: happy soil, happy plants

There are two magic ingredients for a happy, healthy, productive garden – good rain and good soil. There’s not much we gardeners can do about the weather, but a rich soil, full of nutrients and buzzing with useful microorganisms is well within our control.

Last winter's peas and broad beans had a huge crop thanks to some great soil.

Good soil will give you productive plants – plants that grow strong and tall, that are resistant to pests and disease, and that produce a bumper crop of fruit and veg. There’s a real science to it, so much so that some people study soil for a living – happily, that’s not necessary for the average backyard gardener.

The approach to improving your soil is the much same whether your soil is sandy or, like Canberra dirt, contains so much clay you could make a dinner set by digging a hole in your frontyard. It’s simply a matter of adding organic matter, be it compost, manure, a green manure crop, or a good natural mulch that you can dig in at the end of each season. If you can track down a supply of earth worms, adding several to your patch will do wonders for your soil, which they will aerate and enrich.

Now is the perfect time to do this, particularly if you didn’t get around to planting winter crops, so there’s a good couple of months before you plant into it. This will give the time for the organic matter to break down and soil structure to form.

Seriously good compost - it's magical stuff

Compost – fruit, veg and/or other organic matter that has cooked down to a lovely dark, chocolatey, highly nutritious soil. It can be purchased but there’s nothing like the home-cooked variety (More to come on this). Mushroom compost is a good commercial option for helping improve soil structure, and is widely available.

Manure – from non-meat-eating animals, like horses, sheep or cows. This can be purchased or collected for free if you have the time, inclination and a friendly farmer handy. It is important that it’s left to age first – fresh manure will burn the plant roots.

To use compost and/or manure, scatter a decent amount over the soil – the more the merrier really but up to 5cm is good – and fork it through the soil.

Green manure – this is where you scatter plenty of seeds over the garden bed – peas, beans, lucerne, barley, mustard, or a combination, rake in, and leave to grow for several weeks as a thick luscious green mess. When the plants have  grown to around 40cm high, chop them up roughly with your spade and dig them into the soil. As they break down they’ll give a great nitrogen boost. It’s important not to let the plants flower first as that will use up 95% of that goodness before it can get into the soil.

Strawberries surrounded by a straw mulch

Mulch – dried lawn clippings (not fresh), pea straw, sugar cane mulch or lucerne straw all make a good mulch. Simply add a 5cm layer on top of the soil and around your plants to help retain moisture and protect the roots from the summer heat or winter cold. At the end of the growing season, dig the mulch in and it will break down beautifully.

Your plants will eventually use up the good stuff (I once had a large gum tree that literally ate three tonnes of dirt over a two-year period), so lightly fork more into the soil a few times during the year. It sounds like a big investment but really, keeping your soil happy and healthy takes a couple of hours every few months, and the reward is well worth it.

This crop of sunflowers came from a load of horse manure dug into the garden a couple of months earlier.