How to build better soil in any garden

Nearly every garden problem that gets blamed on the plant is actually a soil problem, and nearly every soil problem has the same answer. It is the least glamorous part of gardening and it is the part that decides everything else.

Work out what you have got first

Grab a handful, wet it slightly and squeeze it.

• Sandy. It falls apart as soon as you open your hand, and it feels gritty. Water and nutrients run straight through it. Very common around here.
• Clay. It rolls into a sausage and holds its shape, and it feels slippery. It holds nutrients well and water badly, so it waterlogs in winter and sets like concrete in summer.
• Loam. It holds together and then crumbles when you poke it. This is the one everybody wants.

The useful thing about this is that the fix for sandy soil and the fix for clay soil are the same fix, which is organic matter. It opens clay up so water can move through, and it gives sand something to hold water and nutrients against. One answer, both problems.

pH, and why it matters more than people expect

Soil pH decides whether the nutrients already in your soil are available to the plant at all. Get it badly wrong and you can add all the fertiliser you like while the plant sits there yellow, because it physically cannot take it up. Most vegetables want somewhere around 6 to 7.

A test kit costs less than a couple of bags of fertiliser and it is worth doing once before you start guessing. If it comes back too acidic, garden lime lifts it. Too alkaline is harder and is usually handled by adding organic matter and growing what suits.

The three things that improve any soil

Compost

Kitchen scraps, grass clippings, leaves and prunings, and the ratio is the bit most people get wrong. Aim for roughly two parts brown to one part green by volume. Browns are the dry carbon materials, leaves, straw, cardboard, dry prunings. Greens are the wet nitrogen ones, food scraps, fresh clippings, manure.

Too much green and it goes slimy and smells. Too much brown and it just sits there doing nothing for a year. Turn it when you think of it so it stays aerobic, keep it about as damp as a wrung out sponge, and you will have something usable in a few months.

If you would rather skip to the end, a bagged compost does the same job on the day you buy it.

Mulch

The laziest useful thing in gardening. It keeps moisture in, keeps the soil temperature steadier, stops the surface crusting and smothers weed seedlings, and then it breaks down and becomes the organic matter you were going to dig in anyway. Pea straw, sugar cane, bark or grass clippings all work.

Keep it back a few centimetres off stems and trunks, because mulch packed against a stem holds moisture there and rots it.

Leaving it alone

Soil has fungal networks and worm channels running through it, and every time you dig it over thoroughly you break all of that and start again. There is a place for digging compost through a brand new bed. There is much less of a place for turning a bed over every season out of habit. Laying compost and mulch on top and letting the worms take it down is less work and it does more.

Rotate what you plant

Different crops draw on different things and host different pests, so growing tomatoes in the same square metre year after year runs that patch down and builds up whatever likes tomatoes. Move the groups around: leafy things, then fruiting things, then roots, then legumes to put some nitrogen back. It costs nothing and it is one of the oldest pieces of advice there is because it works.

Shop related products

• Brunnings Garden Compost with Seaweed 25L. For working through a bed now rather than waiting on a heap.
• Martins Organic Pea Straw Mulch 11kg. A bale goes a long way and it adds nitrogen as it breaks down.
• Martins Organic Sugar Cane Bale 11kg. Finer than pea straw and tidier looking on a front bed.
• Manutec Soil pH Test Kit. Do this once and stop guessing.

More in the Brunnings range, Neutrog and the garden centre. Bales and bags are awkward in a boot, so local delivery is $5 in Strathalbyn and $10 on the regional run.

Did you know we also stock garden lime, gypsum for breaking up clay, and blood and bone in the shop, along with Cyclone and Gardenmaster forks and spades. They aren't all on the website, so give us a ring on (08) 8536 4333 to check what is on the shelf.

More from the garden

• How to make compost at home without it going wrong
• How to get garden soil ready for autumn planting
• How to prepare your soil for a winter vegetable garden

Dirt under the fingernails, as usual, and I would rather talk about soil than almost anything else in the shop.

Cheers,
Candeece