Here’s the question today: When should I till in my garden? I was talking to my dad about tilling. I’ve read in various places that tilling can be detrimental…but in a home garden it is a common practice to prepare sites for planting and get rid of weeds.
The short answer is you don’t need to till at all. If you want to, you can use tilling to incorporate organic matter during the initial site preparation, and to break up soils that are already compacted. Past that, I think it causes more harm than good. I’m going to ramble a bit and get into more specifics: feel free to stop reading if you aren’t into detailed explanations.
Tilling is thought to make the soil easier to work with (it doesn’t), control weeds, and incorporate organic matter. But there are also detrimental effects of tilling. These include propagating perennial weeds, bringing annual weed seed to the surface, decreasing earthworms and beneficial microorganism, deteriorating organic matter, destroying soil structure, injuring plant roots, and it also takes a lot of labor and effort.
Some of the perceived benefits aren’t as beneficial as they seem. The first misconception is that tilling will loosen the soil. Tilling actually destroys the soil structure. In farms that are frequently tilled, soil compaction actually increases.
The second misconception is that tilling gets rid of weeds. For some weeds, it does. But it can also increase the populations of other weeds. For instance, tilling quackgrass does a good job of chopping up the rhizomes and propagating the plant. After tilling, the quackgrass will come back more aggressively.
The last benefit of tilling is to incorporate organic matter. For initial bed preparation, tilling in organic matter can help it move down in the soil profile and improve soil health. But continued tilling will lessen the effects, as the organic matter deteriorates.
You don’t have to get very deep in the literature to realize that adopting no-till methods can be very beneficial. No-till systems have better aeration and drainage, more earthworms, and less soil erosion. Most of the research has been done in large-scale crops, but the same principles apply in the home garden.
Home gardeners have the added advantage that everything is small-scale. One issue in till vs no-till is that tilling can be a good weed control method. The other option in no-till systems is often herbicides. But with small-scale home garden, mulch and hand weeding work well.
The alternatives to tilling include:
- Mulching: Includes organic mulch or plastic sheeting. Mulching will reduce weeds and help regulate water. Organic mulch also add organic matter to the soil. Plastic mulch raises soil temperature for earlier planting.
- Smother: Use plastic sheeting, layers of corrugated cardboard or newspaper and organic mulch. I’ve used cardboard topped with a couple of inches of compost to kill off lawn. It takes some time, but does a great job of killing off whatever is underneath.
- Top dressing: Instead of incorporating fertilizer or compost, just apply it to the top and let the earthworms and rainfall do the work. Plant roots are most concentrated in the top of the soil profile anyway.
Tilling can still be useful during the initial site preparation and to help break up soils that are already compacted. Whenever you till, make sure and apply a good layer of compost at the same time. Don’t be afraid to just ditch the tiller altogether: the soil will probably thank you.
*The picture has nothing to do with the post. I was just enjoying the flowers in my tiny garden.
Liz Braithwaite 