No till gardening, how to start it and what it will not fix

March 4, 2025

Digging a bed over every season is hard work and it undoes a fair bit of what the soil has spent the last few months building, because the fungal threads and the worm channels and the crumb structure all get chopped up in the process and then have to start again. No till gardening is the alternative, and the principle behind it is simple enough. You feed the soil from the top, the way a paddock or a patch of scrub does, and you let the worms and the fungi do the mixing.

It works, it is less work once it is established, and there are a couple of situations where starting no till without fixing something first will quietly waste you a season. Those are worth knowing before you buy a pallet of mulch.

What leaving the soil alone actually does

The structure stays put. Fungal threads and worm channels are what let water in and air down, and a fork through the bed cuts the lot.
Fewer weeds come up. Every time you turn soil you bring buried seed up to the light, which is why a freshly dug bed greens over in a fortnight.
It holds water better. A covered soil surface stays cooler and loses far less to evaporation, which matters more here than it does in most places.
The surface stops washing away. Bare soil on any sort of slope moves in the first decent rain, and a mulch layer keeps it where you put it.

The two things to sort out before you start

This is the part most no till articles leave out, and it is the part that decides whether your first year works.

Compaction. If the bed has been driven on, walked on for years, or has a hard pan under it, the worms are not going to fix that for you in one season. Break it once, with a fork rather than a rotary hoe, lifting and levering rather than turning the soil over, and then never dig it again. One pass, the year you start. After that the no till rule holds.

Perennial weeds. Annual weed seed stays buried and that is the honest win. Couch, kikuyu, oxalis and nutgrass are a different animal, and all four will come straight up through 100mm of mulch and be growing happily in your new bed by spring, with the mulch making them harder to get at rather than easier. Deal with those before you cover anything.

Starting a bed over lawn

Mulch on its own will not kill grass. What does work is a smothering layer with the mulch on top of it, so lay plain cardboard over the area with the tape and the plastic labels pulled off, overlap the sheets by about 100mm so nothing finds a gap, and wet it through properly before anything goes on top.

Then build up: a layer of compost or aged manure, then straw or a bagged mulch over that, to a total of something like 150mm. Water it well and give it 6 to 8 weeks before you plant anything into it, which is the bit everybody skips and then wonders why the couch came back.

Planting into it, and the mistake to avoid

You do not plant into the mulch. Mulch is a surface layer, it dries out fast, and a seedling sat in it either dries off or goes yellow while the breaking-down straw pulls nitrogen away from its roots. Pull the mulch aside, make a pocket of compost or garden soil down at soil level, plant into that, and then draw the mulch back around the seedling with a few centimetres of clearance around the stem.

Small seed sown direct is the other one that catches people. Carrot and lettuce seed will not come up through a mulch layer, so rake a strip clear, put down a fine layer of seed raising mix, sow into that, and mulch either side of the row rather than over it.

Keep the mulch topped up and watch for water sitting on top

The whole system runs on adding material at the surface, so top the mulch up as it breaks down rather than letting the soil go bare. Compost and aged manure once or twice a year will do more for a bed than any amount of liquid fertiliser.

One thing to watch on our sandier soils is water beading up and running off the surface instead of soaking in. Hydrophobic soil under a mulch layer is easy to miss, because the top looks damp and the root zone is bone dry. Push a finger down 100mm after watering, and if it comes back dry, a granular soil wetter through the bed will fix it faster than watering for longer will.

Give a no till bed a couple of seasons before you judge it. The first year is mostly you carting material and waiting, and the difference shows up in the second one, which is not the most exciting sales pitch I have ever written but it is the true one.

Shop related products

Brunnings Garden Compost with Seaweed 25L. The layer that goes under the mulch.
Naturally Good Cow Manure 25L. Aged manure for building a bed up.
Easy Wetta Garden Mulch, 50L. Bagged mulch for the top layer.
Neutrog Whoflungdung Mulch 20kg. A finer mulch that feeds as it breaks down.
Brunnings Seed Raising Mix 5L. For the sowing strip, so small seed has something fine to come up through.

Did you know we also stock bales of lucerne, pea straw and sugar cane, a 90L mulch block and a granular soil wetter in a 2.5L tub, none of which are on the website, so give us a ring on (08) 8536 4333 to check what is on the shelf.

The compost, the mulch and the rest of it are in the garden centre, and if you are building a bed from scratch and cannot fit the bags in the car we run a local delivery service on Tuesdays and Thursdays.