Till vs. No-Till

A 3-D view of tilling in Russia c1915

My post on lasagna gardening, which linked to a brief article by horticulture professor Linda Chalker-Scott seems to have opened a can of worms, so to speak.  Two issues came up in the comments on my post: the wisdom of using cardboard in a lasagna mulch and the pros and cons of double digging/tilling. Let’s address them in separate blog posts, beginning here with double digging/tilling.

There are some very persuasive arguments in favor of a no-till, leave the soil alone approach. Chalker-Scott in the comments section of her post on lasagna gardening says,

. . . double digging (the equivalent of tilling in agriculture) disrupts natural soil building. No-till agriculture is increasingly preferred as being more protective of the soil ecosystem. I think the same philosophy could be applied to home gardens as well. You’re right, you can boost production with a more aggressive approach to soil amendment – a similar argument is often made in conventional agriculture (compared to organic agriculture) to till, use excessive fertilizers, pesticides, etc. I guess it depends on how you regard the soil – as a medium for growing vegetables or as an ecosystem (and I’m not being judgmental). It’s a philosophical choice.

No-till agriculture advocates argue that tilling oxidizes organic matter leading to a loss in soil fertility and the creation of carbon dioxide which, in turn, leads to global warming. A case can also be made that tilling creates a soil “crust” that interferes with water penetration. And tilling disrupts mycelial networks and other soil organisms that, research has shown, form important symbiotic relationships with plant roots. 

But what about heavily compacted soils? How do you turn a lawn or driveway into a garden? It’s in these cases that I, in the past, have used double digging.

Double digging proponents would argue that the practice should be distinguished from tilling in that, unlike tilling, you don’t invert the soil structure as much when you double dig. Double digging keeps the same soil profile while loosening heavy compaction. Double-digging advocates distance themselves from the use of roto-tilling machines which invert deeper layers of soil with surface layers that contain more organic matter.

But there are alternatives to double digging and tilling that will break up compacted soils. Scott Kleinrock at the Huntington Ranch turned a former construction parking lot into a productive edible landscape without double digging or tilling. Kleinrock used what I’d call a kind of toolkit of de-compaction strategies:

  • The application of a thick mulch (Chalker-Scott suggests a minimum of 12 inches). It’s surprising how many earthworms start doing the tilling for you with a thick mulch layer.
  • Planting soil busting cover crops with thick tap roots like Daikon radish
  • The use of a broadfork or deep spader
Peaceful Valley’s “Deep Spader”
A broadfork in action

Broadforks and deep spaders get air and water into compacted soils without the damage tilling can do. Unfortunately broadforks and deep spaders are very expensive (around $200) and heavy. The deep spader Kleinrock used came from Peaceful Valley Farm and Garden Supply. I’ve tried it and it works nicely, though it’s still hard labor. If you knew how to weld you could probably make a home brew deep spader or broadfork. I’ve also successfully used a regular, inexpensive garden spading fork in moderately compacted soils.

This is clearly a topic on which reasonable people can disagree, but the no-till folks seem to have the upper hand in terms of the science. As with all gardening problems, though, context is king. Environmental factors and economic issues (those expensive broadforks) intersect in our urban gardens in complex ways. You have to make up your own mind. I’d say if you’re going to double-dig do it only as a last resort and after considering all the alternatives. While, under some circumstances, I might double-dig I would never till with a roto-tiller or invert soil structure with a shovel. But after seeing the dramatic improvement in soil at the Huntington Ranch in less than a year, I’m more inclined to try de-compaction alternatives. You could also just build raised beds and import better soil (though that strategy gets expensive).

I’ve created a poll on the right side of this blog on which you can cast a vote on tilling vs. not-tilling vs. double digging. And consider leaving a comment–I’m interested in what readers think about this complex issue.

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33 Comments

  1. I double dig for two reasons. The first is that we have clay soil. The second is that it helps us pull out bindweed roots which are a HUGE problem on our lot.

    However, we don’t do the traditional double dig though. We dig the first shovel depth section and simply move it and then use the spading fork on the soil under that to loosen it.

  2. Fascinating! This is so timely for me. I’ll be starting a brand new vegetable bed in the coming year and have been leaning more towards the ‘no till’ concept. Thanks for this post!

  3. Interesting problem, that. I grew up with a grandfather who believed in tilling every spring, and the garden was run by his instructions throughout my childhood. Years later, I’m finally somewhere where I can garden in something besides pots on the stairs, and I was excited to give it a go – then I found that the unused garden plot attached to my rental house was depleted and compacted clay. We did try to just hand loosen the soil enough to add in organic matter, but it was too compacted. I thoroughly respect double-digging as a valuable tool in very bad soil, or new garden construction, but with a bad back, that wasn’t an option either. I caved, rented a tiller, and did just enough tilling to be able to work some organic material into the top few inches.
    Then, this spring, I wound up just building raised beds. Behind the raised beds, though, I will be continuing to add in organic material at ground level, as I plant potatoes and onions, and hope to improve the soil without needing anything more invasive than my fork and a trowel. Here’s hoping I can attract the earthworms back, and when I leave here, the plot is a workable garden space for the next tenant to enjoy without the labor or worries of tilling or double-digging.

    (And wow, do I want a broadfork, but that’s way beyond our budget – just getting the two small raised beds built was a challenge.)

  4. The biggest problem in my garden is diggers – skunks, squirrels, raccoons, coyotes and even blue jays – that dig up all my vegetables, in fact, everything I plant.

    This Spring I’ve tried something different. I didn’t amend the soil, or mulch it. I just tucked my plants in small holes among the unpulled weeds. The animals have left them all alone. I go through the garden once a week and trim the weeds that interfere with my plants’ sunlight, but otherwise I’m leaving them alone.

    To make up for the lack of amendment I’m also experimenting with cover crops and have a lovely patch of rye, fava and curly vetch going. It’s such a pleasant little patch with bright purple flowers on the vetch – the fava watching over the tomato and rhubarb. I’ll expand on this over the summer, but I’m on my way to being converted to no till.

  5. Hmm… maybe this is a syntax question, but what do you call it when the only tool used is a hoe?

    Because that’s all I do. I put down lots of compost/mulch at the end of fall. In the spring I take the heavy mulch off, and I hoe in the compost, simultaneously hoeing under any early weeds, and any remaining detritus from last year.

    Really I only disturb 2 or 3 inches deep, mostly it just serves to even things out and hamper those early weeds.

  6. I have to do some digging to get the turf off the soil. It’s extremely tough and thick, and as if the grass weren’t enough, it’s held together by interwoven mats of moss. I have convinced myself that I have to take it (the turf) out, and replace it with layers of mulch. I think that at least breaking up the soil with a spading fork would help. But I don’t just have compacted soil. I have compacted clay.

    If you don’t till, how do you incorporate organic matter, which is what everybody says to use on clay soil? I’d like to know what the experts think about tilling clay soil. Or double-digging it.

    And I voted undecided, because I am.

  7. What Teresa said is very interesting, I feel that we (humans) are always making more work for ourself (stuff works if you let it, can’t remember authors name). I like the idea of letting nature do the tilling (earthworms ect) Complimentary planting is something some tribes of native Americans used to employ, they would plant three seeds in the same hole, corn, some kind of squash, and some kind of been. the corn would grow up giving the beans a ladder and the squash would spread out and protect the others with its spiny stems. Diversity = balance = sustainable. Massive mono-crops are axiomatically unbalanced and thus doomed to be un-sustainable, not to mention all the extra work of pushing mother nature around.

  8. I saw a documentary from Ireland or somewhere in the UK that was about the same principles. One man had not disturbed the soil and never fertilized. The adjacent farms had plowed and fertilized for years. The man who did not disturb the soil still had good soil. The other soils on other farms were worn out. It is hard to comprehend that plowing and tilling could be the wrong way to plant and grow food. That said, I am planting in a frame on the ground that is not exactly a raised bed, but no tilling will occur. Chicken mulched leaves and chicken mulched fruits and vegetables will be the only fertilizer or soil, and no holes will be dug. I cannot till, dig, or hoe and have no one to help, so the least work that gets the job done is how I MUST grow vegetables.

  9. Our main garden was put in on heavily compacted clay subsoil. The first year we piled composted manure on the clay and planted in that, kind of like raised beds. The clay was so compacted that water ran through the compost and then off the clay like it was stone. We still got veg to eat though. In subsequent years, we have piled organic matter on top of the soil annually, and planted root crops in each bed to break into the clay. The earthworms are abundant and the soil improves every year. We have never tilled, broadforked, or dug in organic matter, relying on earthworms, fungi etc. to do that. There was no turf on this spot, but in areas where there was turf, lasagna gardening led to the most beautiful soil in one year, much more quickly than in our post-construction wasteland.

  10. You can look at the 3-D photo shown at the top even without a viewer. Just get the distance from your eyes to the screen correct (move your head back and forth) and try to look at both pictures at once (some people try to look at one with each eye). When you get the correct distance, you will see a 3D picture pop out in the middle of the two photos (they will still be visible in the background). It basically works like those MagicEye books. I only learned this recently, to look at 3D proteins in a biology class, so I thought I’d share.

  11. I lasagna gardened (without the cardboard or newspaper) an area of yard that had previously been covered with landscape fabric and rocks. Before I started, the soil had a compacted and rock like layer (hardpan, I’m thinking) about 4 inches down. After a year of the layered materials just sitting on it and me ignoring it completely, I dug down again and the entire layer had softened into just sand. There is a lot of biological activity going on there, whether you see it or not. It’s good to trust that.

  12. “But my conditions are special, I have crabgrass, bindweed, clay, sandy, dry, wet, toxic, fill in the blank soil. I need to waste time and money and ruin my back. Everyone here in my city, town, desert island says so!”

    Everyone thinks they have a problem that can only be addressed with backbreaking labor. Nature does it without intervention. Trust the natural processes.

  13. I followed the concept of double digging, but my soil was so compacted that in some spots I only loosened up the ground to about 6 inches the first time I worked it. Really what I did was loosen the compaction, try and break up the heavies chunks, and then amend the crap out of it: compost, steer manure, rabbit poop, sand, some white stuff that I can’t remember the name of. Each season I amended more (mostly compost, but for each plant I also added some organic fertilizer to give it a boost), and now the soil is crumbly and rich and full of earthworms. I still add compost as I plant, and am going to start some mulching this year. Because my soil is clay, it has lots of nutrients but it gets compacted easily. I never walk on the planting beds, the compost I just spread around the top and let the earthworms do their thing. If a bed is still pretty new though, it requires a couple seasons worth of breaking up the compaction and heavy amending, especially if we get a lot of rain.

  14. Man, it took us two weeks to take out a 3×3 foot square of our lawn by digging the sod out from compacted rock hard Los Angeles dirt. When I picked up your book and read about lasagna gardening, I covered up and killed off the lawn in one evening of newspapering and mulching with compost. Granted some rogue grass would start to poke through because I didn’t have enough newspaper and it turned out really costly (it’s cheaper if you can find somewhere that sells in cubic meters, though we live too far for it to be cost saving)…. in the end that was worth not spending a month trying to accomplish the same thing. And the earthworms loved the dead lawn and newspapers :P

  15. i have raised beds, and rarely double dig, this year being an exception because i got a lot of manure to put in and utilized 2 old compost heaps, so decided it was the 3 yr revamp…normally i like the ruth stout method of a good thick layer of mulch which once a year i will top over with compost …

  16. My “special circumstance” is being broke! I can’t afford to buy the extra amendments I would need to do lasagna gardening or raised beds. I do have tools and time. I double-dig to clear sod when I make a new a bed, but I leave it alone after that. Any future amendments are added as I plant things.

  17. $200 is a bunch of money to spend on something that won’t penetrate my rocky compacted desert soil, and will probably be damaged by it. I am more likely to try plain sheet mulching without digging rather than buying a new piece of equipment. Still I have a pick mattock, a shovel, digging fork, and “caliche bar.” should I chose to dig down and sift out the rocks. But that might not be needed. I saw a message from one poster that stated that he just put the mulch on the compacted ground, and left it there over several seasons, and was surprised at being able to dig down deeper. The mulch had somehow loosened the soil below. Was he lying to me, or mistaken??? Not sure but it makes me think.

  18. Over the seasons, we’ve become big advocates of no-till agriculture. It started with a desire to make our gardening activities more sustainable by decreasing the need for amendments as well as human labor.

    While searching for info on seed balls, Lovejoy came across Masanobu Fukuoka’s no-till, herbicide-free Natural/Do-nothing farming. We both begun nerding out on the topic and studied some very informative videos by one of Fukuoka’s proteges, Emilia Hazelip.

    The basis of Fukuoka’s approach is to maintain the integrity and fertility of the soil foodweb through constant growing of cover crops/green manures, sheet mulching of spent plants, and disrupting the soil as little as possible.

    Now, our Highland Park backyard is a living example of how no-till gardening can and does work. We try to keep things constantly growing, keep the soil mulched, and let nature do the rest.

  19. I too am glad for this post – I was more or less convinced by the no-dig theory but recently did a biointensive-based gardening class where double digging was sold as the way to create beautiful soil (and they really did have beautiful soil – it was at the Alan Chadwick Garden at UC Santa Cruz). So now I feel conflicted. The people there double dig mainly (I think) as an educational tool for their apprentices but the soil needs very little amendment – basically just adding a thin layer of compost every year and green mulching in the winter. It has gone from clay to lovely 4 foot deep loam (over 40 odd years that is). Double digging there does not seem to have damaged the soil one iota, although they said they wouldn’t really need to continue the practice if it wasn’t for the training element.

    I am moving into a new garden this week and really thinking hard about how to manage the soil there. It is great to have some food for thought!

  20. I have been slowly warming up to the idea of no-dig and am experimenting with it this year. One thing that pushed me over the edge was our experience this year of moving our compost bins. Our compost bins had been in place for four years over top of heavy clay soil. This year we moved them and scraped up the compost until we were down to the previous ground level. The soil looked good, but then we stepped on it for some reason and kind of jumped back – it was totally completely spongy and had never been dug. I assume, but don’t know, that this was the action of earthworms. Instead of just leaving that area to go back to grass, we planted berry bushes straight in it.

    Now, 4 years is a long time to wait, but I’m not sure I would have ever been convinced of the no-till case until I saw an example for myself.

  21. If you’re an Elliot Coleman fan, his favorite seed company, Johnnny’s Selected Seeds, sells a few broadforks, the cheapest starting at $159. Still not cheap, but the difference can buy a lot of other supplies. Anyway I’m of the no-till mindset, excluding my initial battle with the horrid native clay, which also includes removing plenty from the garden altogether. And replacing with sandy loam is so, so wonderful!

  22. @Juburdine: No, that other poster didn’t lie. It’s miraculous and hard to believe, but if you just put down thick mulch (1 foot) and leave it sit for a year or so, you will see significant improvement in your soil.

    We’ve also seen great things done with daikon radish at the Huntington Ranch. Daikon seed is available cheap in bulk. Toss that around, let it grow–it’s not fussy, being in that tough mustard family. The huge tap roots bust open the soil, tilling without tilling. That, combined with mulching after the diakons have grown (they grow fast), can really improve soil over a year or so.

  23. I lost my job a year ago so, as you might imagine, our garden is very important to us. I can not spend excess money driving around collecting compostables nor does my kitchen produce enough waste to layer for a garden that produces ALL of our food. The reality is that my garden MUST produce everything to feed us and the soil. BioIntensive growing seems to be the only method that does this. Double digging is something I never wanted to do, but it greatly improved soil fertility and only has to be done every so often. I see no problem with this minor disruption, because if your soil is healthy the fungus, worms, and other soil life are able to recover quickly. Tilled soil is dry and looks dead, but I find lots of works when double digging and soil moisture is not lost nor does it seem to stop the mushrooms from cumming up during the wet season. Well, thats my 2 cents..

  24. I use a pitchfork as a substitute for the expensive spader. It get the job done on our small lot.
    But, yes, we never “flip” soil, just loosen some of the heavy clays we have here in VA. I just think of it as a big aerator.

  25. What amazes me about this century is that it is full of people who either have no knowledge of the centuries past, or they have been duped into thinking all modern thinking is better than the old days. I call that BS.

    Deep tilling has taken place for many centuries. I even have many old farm journals and magazines from the 1800s where many experiments were done on the soil to determine the effects of tilling versus light tilling versus no tilling at all. There were very little effects at all. But somehow, modern thinking know-it-alls believe their unsurpassed “knowledge” makes the past obsolete. If you pay close attention to the early 1900s, you will see the huge profit driven lies that invaded the farming world. It was an attempt to redefine farming for the sake of selling new and improved methods and tools. This is no different than what is taking place today. “Don’t buy a tiller, buy a spade!” “Buy our product and save the environment!”

    All those same slogans were used decades ago. Our current generation has been fooled into ignoring the past for the sake of profit! Tilling works. It always has. It always will. You people are carrying false knowledge. I don’t care how many textbooks or so-called studies make their claims. They are all lies. Any person can take a tiller, dig deep, throw in the proper amendments, and grow to their heart’s content. Anyone who says otherwise is a fool or a liar. Its that simple. I speak on behalf of many centuries of farmers.

    • Anonymous, I couldn’t disagree more. Not sure which old publications you are basing your standpoint on, but I have seen the condition of soils on commercial lands, and seen the condition of soils on organic/no till farmlands – the difference is chalk and cheese. The big picture is that conventional tilling robs the soils, whereas no-till methods enrich and enhance the soil, and we all need to stop thinking about our immediate needs/wants, and focus on what the earth will be like in the future, given what we’re doing to it now. I’m not sure if you farm? I do, and have seen the results for myself – no-till farming, with all that it embraces, is the only way forward. We cannot carry on depleting the soil, polluting our water and destroying natural insect/worm and microbe habitats, if we hope to leave the planet in a better condition than we found it, for our children.

  26. Good threads…but if I may suggest something…in ur post plz let us know if u live in a humid or arid area, lots of rain…no rain…because every situations r different. From experiences n observations if u live in arid not much rain area…u do not really need to cover ground to produce soil…u need first to introduce n trap moisture by eliminating evaporation..so cover may help..n keep some matter under but close to soil surface. If very rainy area..soil must always be cover..manually or naturally so absolutely no runoff of soil. But at same time no waterpooling either..naturally this will kill many soil bios. In short.soil building is moisture. Things to hold moisture. More things to hold moistures which builds more matter which adds more capacity and holds more moistures.no water pooling..pooling is for the river n ocean. the microbes r already present in a handful of dirt…the conditions just needs to be right n they flourish again…the beauty is that life itself is very resilient. Rocky soil…hard clay so..sandy soil…no problem. Don’t. Wash them soil away before momma get enough time to build some more

  27. I’m thinking of tilling for the first time since our garden was planted 5 years ago. This year cutworms (I’m pretty sure – no evidence of snails or slugs and I have seen cutworms and what I believe to be their pupae) ate every seedling I planted. Everything I’ve read so far leads me to tilling as the best way to disrupt their life cycle and prepare for a better 2013. I would appreciate your thoughts. I live in the mid-South.

  28. I like the blog!! But I’m racking my brain..I found I thought a ..digin..tool..but..it’s made of Clay?? Did they do that??

  29. Pingback: Weed Invasion!! 10+ Things You Can Do Once Weeds Have Taken Over Your Garden. - Little Mountain Haven

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