If you do this back breaking work do not leave you soil bare and exposed to the ravages of the sun, wind, and rain for any length of time, grow a cover crop on it. You couls mix in clover hay, or any other kind of hay, or straw, or tree leaves, or any other kind of organic matter, and you shoyuld do that too but never, ever leave soil bare for any length of time. Always grow something in that soil to help prevent erosion and to add more organic matter to that soil.

If there was a way to "till soil to perfection," Mother Nature would have created a creature that does it for you. Instead she created large animals that walk on the ground and deposit manure ON TOP of the soil. Then she has insects which, under good conditions, redeposit the manure into holes up to 10 feet deep. Those beetles that do that do very little to disturb the soil structure. Your rototiller does everything possible to disturb the soil structure.

I've been reading these forums for years (and years). The best results seem to come from the lasagna methods where stuff is piled on top of the soil as a mulch. Two or more inches of mulch left alonw for 6 months will prepare your soil better than a tiller. An alternative is to grow a cover crop of a legume (like vetch) and leave it as tall as practical until you are ready to plant your real crop.

I go with dchall on this one, even though his logic is, shall we say, well drained.

If double digging were easy, I'd say do it once at the start of a new bed and think of it as extravagant sheet composting.
BUT IT'S NOT EASY. And yes, I mean to shout when I say that!

A hairy vetch cover crop will do that work for you. The roots go very deep, and when the cover crop is cut down the roots rot in place and leave their spaces open for air and water to move.

Most of the soil food web and plant nutrition is happening in the top six inches. Below that level, the oxygen starts to deplete. That's why in land fills they cover the garbage with six inches of soil to consider it sealed. And that's why six inches of fill dirt pushed up to a mature tree will kill it. The deep roots bring up water and minerals for sure, but most of the action is in the top six inches, especially for little flowers and vegetable.

You're better off working those six inches to start off (like you already have) and planting cover crops. Never till again, and never walk on your beds. This is very important.

The mulching and top dressing grows a healthy population of worms. The worms make their tunnels under ground, and these tunnels let water drain and air penetrate. More than that, their movement actually works as a piston to pump air around. The bacteria in the soil need this air to digest organic matter and release all the nturients plants need.

The question is not if it is easy or not. The question is if double digging will improve the soil. The answer is, it depends. By turning the soil you will do some pro's and con's.

The pro's of double digging: 1. You are able to break up the soil and incorporate a lot of organic material deep down. 2. You can really imporve the soil's drainage by doing this (if you add lots of organic material at the time). There is absolutely no benefit to turning the soil to loosen it if you do not add any organic material at the same time. It is not turning the soil that makes the soil loose, but the organic maerail. Ahahhh what a concept. 3. You do not have to wait months to create a finished garden bed. 4. Once the bed is established this is a onetime operation. The soil is kept loose by putting additional organic material on the surface and letting the water take it down into the soil. 5. If you have used good composted materials you can plant in the garden in a few days (after letting the soil settle).

The con's of double digging: 1. You will bring up weed seeds that have not seen the light of day for decades and will then sprout. This, however, will be a onetime thing. 2. You will be exposing some bacteria and fungi to the sun and air which will cause them to oxidize (die). However, when you add lots of compost to the soil you will be more than replacing those that oxidize. 3. You risk digging in the soil when it is too dry or too wet. If it is too wet you will press much of the air that is in the soil out. If it is too dry you risk pulverizing the soil, which destroys the it's structure. Both are not good. However, if you wet the area well and then double digg the soil when it is moist (not soggy or dry) you will not do either.

There really are only two questions that you need to ask yourself: When do you want to plant in the garden space and are you (or someone else) physically able to dig the area. The larger the area the more difficult the process is going to be. When I double digged my garen area ten years ago I added so much organic material. The new material more than made up for any lost microbial life that was lost to oxidization. The increas in weeds were not as bad as I was expecting.

I believe in the principle of not tilling the soil, but doing it to get the garden started is not a problem. Every one of the negatives can be dealt with. What is not a good idea is to till the garden evey year - or ever after it has been done initially. I don't even have a problem usig one of those big tillers if your garden is going to be large (say 20x50 ft) so long as you do it right and only do it once. If you are adding lots of compost to the soil each season and a good organic fertilizer that feeds the microbial life you should never have to turn the soil again - ever. There are those who say to never till the soil because it brings up weeds and kills some existing microbial life. But all that can be dealt with.

If you have the time (six months or so) spread a good organic fertilzer (one cup for every 4x4 feet) topped with three inches of good finished compost. Water this well a couple of times a week. The water will take the fertilizer and microbes in the compost into the soil and the microbes will do all the work of loosening up the soil for you. You will be able to dig the soil with a teaspoon in four months. However, if you want to be able to plant a fall garden then you do not have the time to wait so then double digg it and then at least you know you will never have to do it again. It is easy to be a 100% notill gardener when you have an established garden or six months to wait before planting. No one can tell me that double digging the soil one time and adding lots of organic material is going to hurt the soil.

Tom

One thing you haven't thought of with clay soil. If your clay is like mine then digging a hole and filling it with amended soil will only create a bathtub to catch the water from the next rain. (In other words, you will create a low spot to collect water.)

So what do I do? I use raised beds for some veggies and in ground for others. The in ground ones have had the top 6 inches mixed with compost, manure and a good organic dry fertilizer. After planting the plants or seeds, I wait until things start to grow and then mulch with compost, install a drip system and then cover the compost with some sort of organic mulch.

My way of thinking is that veggies with a smaller root system can work well in a raised bed but the others would really rather have room to spread out. I've pulled tomatoes and melons and found roots that ran out 4' or more on all sides. I just can't see these plants excelling in raised beds. Big rooted plants like this will force their roots through clay if the clay is at least moist.

Wow! Thanks for all the great information guys. Was not expecting such quick and detailed replies so quick. Love this site already.

Well my garden area is not that big (4ft x 20ft) and I don't mind doing the work. I would rather not use a raised bed or the lasagna method as it would require lots of extra material. Besides I'd rather improve the soil I have.

So after tilling and adding a thick layer of compost should I sow some Hairy Vetch and Clover seeds? And then after a few weeks work them back in the soil?

Also, when double-digging how deep should I go? I've got a quality shovel and fork to work with so that's not a problem. Also I was thinking of spraying some molasses (unsulphered) down in addition to the compost. Would this be worth it?

Any other suggestions appreciated. And again thanks so much for the help. Between you guys and the books my next harvest will surely be better.

csrain, double digging will create a raised bed. You can Google the term and get detailed instructions with pictures.

Double digging gets it's name because it's done double the length of an average shovel--the trenches are 10-12 inches deep, and then you loosen the bottom of each trench down another 10-12 inches with a shovel and fork. You still start with a three inch layer of compost put down over the whole bed, and then you backfill each trench with the soil you move from the next trench. The compost gets mixed in during this process. At the last trench, you bring that first trench's wheelbarrow(s) of dirt to the end of the bed to fill it.

The purpose of double digging is to loosen soil and leave organic matter and air channels--so work from the side if you can. If your bed is already cultivated and you find yourself stepping in front of your trench, get yourself an old board to stand on, so you aren't compacting the next area to be trenched while you're working on your current trench.

It's also helpful to be working your trenches away from your dominate hand, so that you move the soil back to your dominate side. Your dominate hand usually goes low on the shovel and supports the weight of a shovel full of dirt--and again I'm thinking of your back--you don't want to find yourself supporting most of the weight with you right arm and having to lean and twist to toss the soil the left. You see what I mean? Take it slow, work in stages over several days (or a couple of weeks!) and think about your back. Take care to keep secure good footing, and don't be all bent over and trying to throw shovels full of dirt like they do in the movies, and don't twist.

Boy, I sound like such an old woman, don't I?

Since it really does little good to get organic matter deep into the soil below where the aerobic bacteria are going to work on it, below about 6 inches, and since that amount of organic matter needed to properly amend any soil is about the same as that needed to make a Lasagna Bed, there is really little reason to double dig any soil. While they are not nearly as quick as digging in the Soil food Web will move organic matter into your soil and do it better than you ever could. Also, as shebear has pointed out really amending clay soils can change them so water flows fairly freely in that spot but meets a wall where the soil has not been amended and therefore cannot go anywhere. That will make an undrainable pond where water will accumulate.

I double dug my nasty clay garden and planted a cover crop with incredible results nobody walks by without saying how great it looks sorry but I can't see a "soil food web" But I can see tomatoes and corn 7 feet tall everything is growing huge and with great vigor

But I used heavy equipment to dig it that most probly don't have althogh you can rent a tractor with a loader and tiller around here for about 100 a day

Also depends on whats under your clay we have gravel vein about 3-4 under the top soil

jonas, if you know nothing about the Soil Food Web below is a link to Dr, Elaine Ingham's excellent primer on it.

Here is a link that might be useful: The Soil Food Web Primer

Jonas you give me hope. Lol. What cover crop did you plant? I was thinking of going with a mix of clover and vetch or alfalfa.

kimmsr, awesome link. Was aware of soil web, but this link gives detailed info. on all aspects of the web. Especially interested in the environment around the roots. Fungus play such a huge role with regards to the roots. I was thinking of mixing in some mycorrhizal pellets with my soil. Thought?

Deep double digging gives you dramatically fertile soil in a short time. No doubt about it. It is hard work though.

I had planted rye because it was cheap here

Kimmsr I glanced at the link will definatly be reading though when I get a chance thanks

There is always more than one way to skin the cat as they say (:

I have three nearly equal sized garden beds. The first one I double-dug. The second I used a tiller, the third I attempted a lasagna bed.

Double-digging is a lot of hard work, but it did give me the chance to amend the subsoil with Sulfur to try to lower its pH. I removed the topsoil (about a foot of soil), dug a trench in the subsoil, and used a broadfork to loosen the subsoil. I worried the surface of the subsoil and mixed in Sulfur and humic/fulvic acid. As I moved the topsoil back onto the subsoil, I amended it with Phosphorus, Sulfur and then lots of compost and coffee grounds.

First year results were not as good as anticipated. I think I had some unfinished compost and that hindered early season growth. This year, I have corn planted on that bed this year. The bi-color corn is over seven feet tall and is just now ripening. The early corn from that bed has been delicious.

I suppose time will tell which of the three beds was the best experiment, but that double-dug bed was a heck of a lot of work.

Molasses is one of the best microbial foods you can use. I don't know that you need to use the molasses in the middle of the process though. Remember, after you turn in all the compost you will have created plenty air spaces for the water to move around. After you are finished mix 2T of molasses to a gallon of water. The water will take the molasses down to where the microbes are. Just be sure to water deep so the water can penetrate. It is usually best to water a little bit at first and then the next day increase the amount of water. Water moves faster, and more efficiently through soil that is already moist. A 1/2 " on Monday, 3/4" on Tuesday, and then a really good soaking on Wednesday. You can also add fish emulsion or fish Hydrolizate to the molasses water as well. Fish Hydrolizate is very good for fungi. Letting the soil alone after you turn it is good for the fungi. While bacteria are so small that they can handle the turning of the soil much better; fungi are not so tolerant of turning. They are really large, in comparison, and turning the soil really puts the hurt on them. If you have a compost pile and have seen long white threads going all through the pile, that is fungi. One other thing molasses does is it provides the microbes their own food source. Microbes need energy in order to break down and digest the organic material in the soil. If they do not have an energy source they will use the fertilzer that is in the soil for their food. So adding some molasses gives the microbes a good shot of the carbon bonds they need and helps reduce their need to compet with the plants for the fertilizer as an energy source.

As you continue to add more organic material on top of the soil and then water it in well you will make sure the level of organic life in the soil remains high. It is the micribrobial life (bacteria and fungi) that are getting in between the clay particles that prevents the clay from sticking together. In addition to loosening up the soil, bacteria is also a worm attractant because the bacteria are worm food. Worms do not have teeth. Worms do not eat leaves, sawdust, or vegetable scraps, etc. they eat the microbes in the soil. As long as you keep the garden area moist the worms will hang around and do even more great things for the soil - like tunnel holes and leave their castings in the soil.

When I double digged my garden I took out a full shovel full of soil and laid it to the side. I then looseded up another shovel full of soil in the trench. I then added a whole bunch of compost at this point. I then put back the first shovel of soil and again mixed another good amount of compost with this. Always moving from the trench I just dug to the new hard soil. That way I was not trampling all over my freshly dug trenches. You don't have to do a trench either. You can dig out a 3x3 square area and to the same thing moving from sauare to sauare. I found this worked great on my second bed. As far as the person who said that all you will do is create a hole for the water to accumulate, the idea is not to make individual holes. The idea is to do the entire bed. By doing the entire bed you allow the water to move from the high spots to the low spots and hopefully this will allow enough time for the water to drain. But you would be right if you only did individual holes, you would get little wells where the water collect - not a good thing.

The important thing here is that it is the microbes in the soil that loosens up hardpan soil - not the tilling. The tilling/turning is only the mechanism that is used to get the organic matter down deep, fast. It is the microbes that provide a food source for the worms. And it is the microbes in the soil that break down the fertilizer and put it in a form the plants can use (I am talking organic fertilizers here, not chemical fertilizers). Plants also break down fertilizer by mixing CO2 with the water in the soil. This makes an acid that disolves the fertilzer which allows the plant to then take it up.

Just mix in lots of compost and you will be set.

Tom

Some really good info avid hiker. I think I'm starting to get it. Tilling allows microbes and other beasties to flourish, allowing the plants to flourish. Feed the soil not the plant. Living in Houston, good sources of compost are not readily available (as opposed to a farm town). Are those bags of compost from Lowe's or Ace any good? I know they may be devoid of life from sitting in a bag in the sun for a while. Would they be usable after they breakdown and regain life thro0ugh molasses and the surrounding ground soil?

I was in Armstron nursery a little while ago and I put my hand on a bag of compost and I thought I had burned my hand. I told one of the guys there that they needed to pu t a shade covering overhead to help keep the hot sun off the bags. When I said that the heat was cooking all the life out of the bags, like composting does. I could tell he understood what I was saying and that he said he would bring it up with the owners. That was three months ago and still the bags sit in the sun. Here in SoCal it is normal for the daytime temps to be in the mid 90's. I did notice that the bags of vermicompost are inside in the shade. So, I don't buy any compost from that nursery. I had to go to two other nursery's before I found one that keeps their compost under a tarp that is supended about 10' in the air. Their bags of compost were nice and cool. I let them know I was happy about the shade covering they had and that I am buyihg theirs even though there is a nursery much closer to my house. He appreciated my telling him that.

In the end, I guess it is not absolutely critical to buy it that way. You are going to be able to rebuild the microbial life in the soil by adding some molasses to to the watering water. Just use a good organic fertilizer. Organic fertilizers add so much more than just NPK. They add humic acid, bacteria, and other stuff that the chemical fertilizers don't. It is nearly impossible to over due the organic fertilizers as well.

I am sure there has to be some kind of independent nursery in your area. You know what just cracked me up. A little while ago I was in Lowes getting some paint strainer bags so I could make my aerated compost tea. I went out into the garden center to take a look around and I saw the funniest thing. In the center of the yard I saw the open structure that held the cement, plaster, aggregate rock, etc. All this stuff was in the center of the yard and totally shaded. I don't think the sun hit it at any time during the day. Out in the perimeter were the bags of complst, vermicompost, manures, etc. All these things were sitting in the hot sun. I walked up to the bag of worm castings and (just like what happened to me at Armstron nursery) my hand practically burned. I could not believe it. The rocks were in the shade and the organic material baked in the sun. I just smiled. I guess I go overboard a litle sometimes. Because people put the stuff on their yards and the yards look great. IT is just that when it comes to my veggie garden I seem to want to go the extra mile and get the best stuff I can. That is why I am going ot put a lot of Charcole (the new fancy name for it is BioChar - it is charcole for goodness sake) into my garden this fall. Not the kind of charcole you buy in the store for the BBQ, but the kind of charcole that is made from buring wood in a low oxygen environment. The charcole seems to imporve the environment for micro organisms and provides a way for the soil to hold on to the fertilizer nutriants better. I am going to experiment by putting it into one section of my veggie beds and then see if the results are as implressive as some have claimed.

Anyway, good luck with your garden bed. Be sure to foiar spray your plants with fish emulsion bimonthly and molasses monthly. No need to use molasses more often than that once the beds is established. If you use molasses too often you will create an articial environemnt. I always add molasses after I add compost because all the new microbes need energy and they are not well established in their new ecosystem yet. But after a monthe or so the new population will be doing their own thing just fine. As long as the soil is kept moist the microbes will be happy. Did you know that molasses is phenomenal at getting rid of spider mites? If you have spider mites then use 2T in a gallon of water as a foliar spray weekly.

Tom