When to Amend Garden Soil and When Not to.
The two types of garden soil that really need to be amended the most are clay soil and sandy soil. Clay needs to be amended to loosen it up. The roots of plants need to have the ability to transfer oxygen through the soil to the root system. That’s why plants do so well in loose soil.
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The best way to amend clay is to work into the soil as much organic matter as possible. Rotted leaves, rotted grass clippings etc. Ideally, if you have this material in a compost bin giving it a chance to break down before adding it to the soil that would be perfect, but not necessary.
Watch our Mantis Tiller video here.
Wood chips should only be added to soil after they’ve been sitting for at least 3 years, giving them a chance to break down before adding them to your soil. Fresh wood chips need a lot of nitrogen to decompose, and if in your garden they will pull that nitrogen from your existing soil, depriving your plants of the nitrogen that they need.
We have another Mantis Tiller video here.
The more organic matter you add to your soil, the happier your plants are going to be.
Do not remove soil from your beds before you start amending the soil. Doing so will create a “bathtub” where water can get into the bed, but will not be able to drain out. Not good for plants! Plants do not like “wet feet”. Just put the organic matter on top of the soil and mix it in by hand or with a rototiller.
If you have really sandy or gravel based soil in your yard it’s a good idea to amend with organic matter just to add extra nutrition to your soil. Most plants actually love sandy or gravel soils, so when you add organic matter to these soil to take a good soil to a superior soil that plants will thrive in.
The rest of this discussion started out as a post on my private website for backyard growers and their potting soil mixes. This is what I wrote . . .
There are a lot of people that are sure to tell me that I’m doing it all wrong because . . . I’ve never tested my potting soil. All of the plants that I grew and will grow this year in that soil did great! Those that didn’t? I figured they were just too wet which happens a lot with potting mixes. Potting mixes need to drain well so the plant roots can breath.
Some people have really poor soil in their yards.
One thing that I try and remind myself of is that really, really good soil is topsoil that contains a lot of organic matter that wasn’t put there by anybody but Mother Nature. Topsoil is nothing but rotted organic matter that has rotted so well that it turned into really, really rich soil.
So when making a potting mix, I try and mimic that. Lots of rooted organic matter, then enough loose material to makes sure the roots can breath and the water can run through.
PH? Not sure what the PH is. Never tested for it, never had a big enough of a problem to be concerned about it.
Now, with all of that said, if I were to decide to grow nothing but Rhododendrons, tens of thousands of them for the wholesale trade, container grown, I’d probably have the soil tested to make it as perfect as possible. But since my nursery is nothing but a big batch of mixed dogs, no point trying to make any one particular plant happy. I just make generic soil that makes everything happy.
Years ago I planted 705 Rhododendron in the field. 600 at my friend Larry’s house, soil wasn’t bad, but a little sticky. It was clay soil, but not ugly, ugly clay soil. Great for Forsythia and dogwood trees, but the Rhody’s grew slow. They didn’t look bad, they just grew a little slow.
The other 105 wouldn’t fit in Larry’s yard so we planted them down the road from my house on land owned by a mutual friend. Some sand, mostly gravel, lots of big rocks! I mean digging a hole you could see sparks coming off the spade. Those kinds of rocks.
We didn’t amend the soil, we just planted the 105 Rhododendron. No water on the property and the soil drained like kitchen colander. It was dry. That batch of 105 Rhododendrons thought they were planted in heaven! They grew like weeds! We sold that batch two and three years ahead of the ones in the sticky soil. They loved that rock farm.
The lesson? The magic wasn’t in PH or soil amendments. Rhododendron hate wet feet more than anything in the world. All we did, (by accident!) to make them happy was to give them nice dry feet.
No rocket science, just common sense from the perspective of the plants. We can read 100 books, but until you experience a few accidental tests like that you really don’t get that it’s really about what the plants want, not what the book says, or what the professor says.
The professor? He’s never risked his grocery money on a thousand plants in hopes of paying a few bills. His bills are paid. He’s a professor. He doesn’t take chances. He’s really smart, he doesn’t need to gamble. He’s wired to take the sure bet and get a pay check every week. The rest of us? We’re in it for the game and the chance of the bigger reward.
Nothin against higher education. It’s just not my cup of tea. But the true irony is when I get an Email from a horticulture professor asking permission to use my backyard growing system in the classroom. It’s happened more than once. That’s all the compliment that I need. My hat is off to the scholarly type that realizes knuckleheads like me actually have real world experience that they can blend with all of that book learnin.
On many occasions people with horticultural degrees have purchased my products because they realized that after graduation college they still didn’t have all the pieces of the puzzle.
You know me, keep it simple. Simple works pretty good unless your putting human beings in a rocket ship and sending them off to another planet. For that, you need to be a lot smarter than me.
Stay inspired! -Mike McGroarty (Who is this Mike McGroarty Guy anyway?)
Johnny Bonsai says
Great info as usual Mike! It’s always great to keep things simple and let the plants tell you what they want.
Hi mike I just purchased the system and I can’t wait to get everything. I’m very eager to get started with a game plan. I have horrible clay soil so I’m building raised beds and filling them with layers of greens and browns. I don’t have access to any plants other than those I purchased at the box store previously and I can’t afford to buy a bunch at full price right now. I”m hoping to learn enough info to get it together by next year.
I’m laid off so it may be another year before I can really get moving. I’m waiting to meet other members and get all the little nuggets of info I can pick up since I’ll have a very small window to get plants in the ground before I get sucked back into the oil dungeon til winter. I’m in construction and it’s killing me. Long hard seasonal work days and saving all the pay for bills during winters off. I’m an industrial electrician and work the local refinery mostly. I dread going back in. I feel like i’m going to war with the man.
I love reading your articles and am looking forward to getting the rest of the system in the mail. I also look forward to learning and sharing with the other growers. When I get access I’ll be doing cartwheels in my dreams hehe. If doing something I love keeps me out of the oil dungeon a little longer then it’s worth pursuing. Thanks again Mike. I appreciate your hard work.
Pamela, thank you so much for becoming a member of our growing family. Construction work? You’ll be perfect for this. I know you can’t do much, but you can do something everyday to grow your business.
Keep making those baby plants. They are better than money in the bank because they appreciate in value at a tremendous rate. Have fun! -Mike McGroarty http://freeplants.com/wanted.htm
I use Considerable amount of eggs and started to save and crush the shells. What do you think of mixing them in
Only trouble I had with that was the racoons would dig down into the soil to find the egg shells.
Judy Hoppe says
Forgot to say that I had no worms on the place when I moved here. They are thick everywhere at present and work from the mulch into the clay a short distance, back and forth, adding soil to the mulch above. Also built 3 compost bins from pallets. Live in southwest Oregon.
Judy Hoppe says
Mike, love your articles and tidbits of advise. I live in black mud country. We tried for several years working lots of mulch into it, but to little avail. Stop for a year and we were back to black mud. Finally started putting gypsum on the mud and building with lots of mulch on top. Eventually we had 10-12″ of beautiful soil to work in. Paths in the gardens were filled 10″ deep with rotting leaves and just sat there. Come spring we would roto-til the paths (which picked up a little black mud, raking the beautiful soft material to either side of the walk, into the beds. The beds got deeper and deeper in beautiful soil. The paths got a little deeper with each leaf layer roto-tilled and added to the beds in the spring.
A friend who had built his gardens with mulch atop black mud for 25 years, decided not to garden there any more. In three years it was back to black mud. That stuff seems to eat mulch for breakfast, lunch, dinner and snacks. Maybe it’s because we have BLACK mud that it won’t incorporate or work well with mulch?
I live in anther area of town now. Our subdivision was built on a swamp, 5′ of blue rock over the top and a layer of ‘top soil’ (sterile sand and clay) on top, anywhere from a few inches to a foot or more deep, whatever it took to level the lot. Rhodies were plopped atop the ‘top soil’ then bark mulch spread on top. Rhodies, 5′ Arbor Vitae and other things were easy to pull out by hand because the roots were only in the bark (automatically watered daily. My house was a rental at the time.) Dig down a few inches and you have swamp slime. Had to put in French drains and raised beds. Started building atop the existing ‘top soil’ with free leaves delivered by the city every year, and some purchased ‘top soil’, clay and sand. They work beautifully together. In 5 years I have transformed the whole place with blueberries, raspberries, strawberries, asparagus bed, apple tree, and raised beds for vegies. All in a small city lot. Fences I put in keep the deer out so far. Wish me luck.
74 this year and glad the worst of it is behind me, though everything will have to get a good layer of mulch every year.
Dear Mike, I’ve been a fan for years now, but we finally (!) have a garden of our own. It’s a newly built property so we have a lot of clay and wetness. The area we live in is very wet. What can we do to a) loosen the soil without damaging the structure and b) dry it up a bit? We’ve just started a thermo compost bin, but there’s not nearly enough organic matter to help us out. We’d really appreciate some advice. Kind regards, Claudia (from Switzerand)
Claudia, thanks for being a fan for years! As long as the ground on your property drains well the clay will dry. But once dry it will get very, very hard. Start working as much organic matter into your garden as soon as you can. That will improve the soil and keep it loose when it gets dry.
Hi Mike ,
I have a lot of experience with clay soil here in the Carolinas. and on important think I would add is avoid walking or going over the soil while it is wet since to do so will severely damage the soil structure by packing it down like a brick. You must wait until it is sufficiently dry before tilling and adding organic matter, it also pays to have a little slope to promote drainage . Compacted soil dries like a brick and plant roots have a hard time , and often if you try to water the water just runs off. If you can’t wait for clay to dry properly , it’s better just to go over it with a raised bed . Try to avoid walking on driving over the soil after planting for the same reasons .
Carol Sue Perkins says
Mike, I have learnd so much from you. Now I’ll have a chance to start all over and put it to use . I’m selling my house in Washington state (sandy soil) and moving to Ridgeland MS (clay soil). It is breaking my heart to leave my yard to new people My yard was on the KOI Club pond tour this past fall and all my visitors loved my yard. But, I have plans for that Mississippi clay soil. I told my son to build me several compost bins. My first activity is to locate a gardening service and see if they will give me their grass clippings. Next I plan to plant peas for nitrogen all over the lot to till in. By 2014 I’ll be ready to plant! Hee Haw!
Alex S says
Clay soil is great soil for growing , very fertile if you know how to work it .
If you want to till it , you should add pine bark fines and a little Gypsum. After one year the soil will be workable . Then there are no till methods, where you add at least 2 inches and up to 6 inches of compost on top of clay, then you add 4 inches of finely chopped wood chips on top of compost , and install plants which will start growing in the compost and end up rooting into the clay and softening it for you . Note don’t till at all , and if you have grass or weeds just put down 2 layers of heavy cardboard on the ground before adding compost . Of course in MS make sure the land is not boggy before doing this !
Great advice Alex. Thank you!
thanks for the insight Mike to NOT dig out my soil! I was planning to do this to amend a clay spot in my yard, & you’ve saved me some heartache. Also, thanks for the consistently useful newsletter emails; I forwarded this one to a couple friends, & I think they’ll both subscribe 🙂
City Mouse, you’re right. I’ve seen people dig out clay and put in topsoil. It sounds like a good idea, but it never turns out well. Once the water gets in it just sits below the surface rotting the roots of all the plants in the bed.
Mike, guess I’m a ‘knucklehead’ too. Planted a tomato plant in late June in my greenhouse that I just set up last winter. Very sandy soil in places as I’m in the forest right off a lake. A week later, temperatures rose into the 100’s and stayed that way for almost 3 months. That tomato plant just kept growing, 8′ high and 8′ spread, set out numerous flowers, but nothing developed. Then the temperature dropped back to normal and the plant went CRAZY with tomatoes! It’s now been removed to begin a new season, but I got over 9 dozen nice, tasty, large and medium tomatoes from it!
Oh, and about PH? What the heck is that? Plant horrors?
Mike, I live in the Arizona desert (a distant suburb of Phoenix) and the soil is horrible. I keep reading that I should have the stuff tested, but I hear you say that all that matters is keeping it loose with organic matter. I’m going to take your advice and add several bags of compost to cheer up my veggie garden. I am tired of so many of my plants, like pumpkins, squash, and watermelon dying before the fruit can mature. Any extra tips for coaxing produce from the worst soil in the world?
Doug, I think if you can make a concentrated effort on adding as much rotted organic matter to your soil as possible it will improve and that will also improve it’s ability to retain moisture longer. Start your own compost bin and beg borrow and steal, okay, not steal, but get as much stuff into that bin as you can. It’s a work in progress, but you might just enjoy the process. Check this out http://www.freeplants.com/composting.htm
Thanks Mike, I appreciate your help and look forward to turning the desert into my own produce stand! Knuckleheads unite!
thanks mike i really enjoy it i also love those rhodys,,,looking forward to summer when we can start planting again..here in china things works differently,very few houses have gardens,, i try to teach them ,they might buy a plant in a pot that flowers or a cactus.. GOD bless you all
Mike, I love your articles, I live in Ohio also and that’s good for me,us being in the same plant zone. I would like to ask about putting compost in my flower beds. How much to use? I heard that you can use too much. How much is too much. Thanks Mike and keep up the good work.
Pam, it would be difficult to have too much compost in a garden. Just make sure the compost is well rotted and not fresh. Too much fresh compost would not be good at first, but eventually it would improve the soil. Compost is nothing more than the topsoil of tomorrow.
Mike, I have always liked you but after this post on Amending Garden Soil, I love you. this is my approach exactly and you said it way better than I could.
Raun, thank you. I appreciate having you as a subscriber!
Casey Milnes says
Good article! Like you I keep my growing simple! Horse manure is the secret for me! I have horses and I use the stuff in my yard and my sisters place to improve the landscaping and the plants respond by growing very well! THe results are clear in the abundance of flowers and veggies that I get!
Casey, that’s great to hear. I get a lot of negative comments about horse manure because of weed seeds in horse manure compared to cow manure, but the secret is allowing it to decompose before adding it to your gardens.
Bruce E. Rosswurm says
Thanks Mike. Appreciate your useful advise
clyde w holmes says
thanks mike i really enjoy all youremails although i am not able to get out in the garden i enjoy watching stuff grow an will not forget the times spent working in the soil every spring again thanks mike keep them emails comeing.
You mentioned not removing soil before amending because you create a bath tub effect…I did this & now have this problem! It was a tree ring the soil was extremely clay like…I added gypsum, compost, pest moss. But when it rains a lot I have water standing…I’ve killed a tree! I have just planted some Daisha’s there they seem to do quite well but I want to plant another tree there. Any ideas as to how to undo this problem?
The way to undo the problem is to raise bed so water runs away from the bed and not into the bathtub that you created. Just don’t raise the soil level on plants that are already installed.
Mike thanks for sharing your years of actual experience with us. “Experience” is the best teacher. I have learned a lot from you, and looke foreward to each of your emails.
Thanks Dave, I appreciate your kind words. -Mike McGroarty
Thanks Mike I have learned a lot from you and I help my friend with her gardening to.
Tom Biesiada says
just getting started as I have retired but street smart is so true as I told a marketing person at the company I retired from just before I left when she asked rudely “I have a degree in marketing do you” I told her as a matter of fact I do its a PHD in the street with 30 yrs tenure and the tuition was very expensive. your advice and video is so easy to useI look foward to spring
Thanks Mike, I love the down to earth way you explain and suggest things.
Florie Alandt says
Thank you so much Mike for all the information you give so generously. I’m trying to get my rhododendrons going fuller…and you just gave me the answer! (rocks, stones, less water).
Thanks Mike. Love getting all the info to make my gardening easier and more productive.
Bill Whittington says
Mike, street smarts goes a long way. Thanks for all the great info.
ruth pappamihiel says
Thanks Mike, ..You are such an inspiration, glad someone else has the same attitude that I have, I plant and give it loving care, water, nutrients, and leave the rest up to nature.. thanks.
I am trying to grow blueberrys without much luck.I believe my PH is to high. What is the best way to lower it?
The Prudent Homemaker says
Soil Suplhur will lower the ph for blueberries. I like where the native “soil” (haha–it’s so hard here the nursery asked if I jackhammered my holes for planting trees when I bought them; they are NOT kidding) has a ph of 8.5 to 9.5. Add a cup of soil sulphur per blueberry plant if you’re as high as I am. Also, cottonseed meal will lower the ph as well as add nitrogen to your plant. Coffee grounds will also add acidity.
My local nursery has cottonseed meal and soil sulphur in large bags; check at yours.
Dana harness says
I am trying everything. Each year I plant the garden(in raised beds) and the crop is not good. I compost and put that in the soil,I have rakes up the leaves and piled them on the top for the winter then tilled them under when planting time comes. Still not good. As for dry, this soil will dry out and turn hard. Any suggests will be appreciated. Tomatoes grow terrible. Green beans are ok. But other than that, I’s sad.
Alice, my suggestion would be as much organic material as you can find. You can probably buy some organic compost locally. I’d till some of that in. Just ask them if what they are selling is safe for a vegetable garden. Some composts are made with sewage sludge. Ideally you should be using your own compost.
The Prudent Homemaker says
Our local nursery sells compost. It’s pricey, but it’s important! I second Mike’s suggestion to purchase compost.
Hi Mike; enjoy every bit of information you send me down email lane.
I wish I could do all the things I would like to do in my garden, but age is catching up on me. Reading your articles just gives me that extra boost to get out there. Thanks for the inspiration.
Andy, if that’s the case then I have done my job! Happy gardening to you!
Sherry Montgomery says
ok from reading above article…i’ve got lots of alder leaves on the ground and rotted grass clippings back in the bush…so getting the wheelbarrow this morning and mixing the two and topping my garden beds..in January…we have no snow here on the West (wet) Coast of Canada…my soil is very gravelly and this all sounds good from what you say Mike…thanks for the positive thoughts created!!
Sherry, you’re welcome. If I can create positive thoughts then I’d like to think I’m making a difference.
Thanks Mike! It never hurts to experiment. Keep those email coming – they are refreshing in the middle of winter (we just got 5″ of the white stuff and my daughter is challenging me to a snowball fight!).
Linda Frazier says
Mike, I have not yet completed building my greenhouse which I should have been using here in VA since Sept. How can I start seeds now to get going in spring? The weather here is crazy==hot several days and tomorrow we are expecting snow.
A lot of my customers start seeds indoors, in a utility room, basement etc. They need light, circulated air, put a fan close so it blows across the flat of seeds and they need to be warm.
John Marley says
I love your real world spin on gardening. I,like you, have learned a lot more from banging my head against the fence than from a book. Us knuckleheads work that way.
JD McCue says
Mike, Thanks for sharing your gardening techniques and real-world experiences with the rest of us knucklehead gardners. I love your humble, down-to-earth style and enjoy your stories and videos.
JD, thank you!
Rose Eskridge says
I love your humble style of teaching us knuckleheads from the country. I want to learn everything you teach.
I pray God will richly bless you & yours. Please, always keep on sharing your love of God’s beautiful earth & teaching us the things we need to know.
Above where it says Website, is that for us to share with you & others what we do for a living? My husband and I sell custom built restaurant booths. They are very popular for homes now days. If not, please forgive me.
Thanks a million!
Rose, thank you for your kind words. Thanks for asking about the website. We don’t allow people to post website here because, if we did, it just turns the entire site into a great big spam fest being abused by people that don’t even care about gardening, they only care about spamming other peoples sites.