For best results, improve the soil in the entire planting area.
When I go to the garden center, after loading my cart with flowers and bushes, I head straight for the soil aisle to pile on bags of manure, soil conditioner, and all the wonderful things that I believe will make my plants happy. But is amending the soil around garden plants really a good idea? Here’s the scoop on how to – or not to – improve the soil in your garden.
Does Adding Amendments to Soil Really Work?
When I dig into the hard red clay soil in my yard, it’s hard to believe that anything will grow, much less thrive, in such poor conditions. Plants need organic matter, air circulation, and proper drainage, and my soil is lacking in all of the above. So my standard practice has been to dig a hole, sit the new plant in place, and backfill the hole with rich organic matter such as manure or compost, and I felt darn proud of the job, too.
But when we amend the soil right around our plants, what happens? In short, we create a pocket of permeable, well-aerated, nutritious soil, surrounded by a wall of inhospitable native soil. And from what we know about plants and soil ecology, the plant roots (and the water, nutrients, and air) have trouble with boundaries.
The tiny feeder roots of the plant will resist spreading out beyond the barrier and instead grow inward in a tight circle. Water will quickly be wicked away into the native soil, or worse, will collect in the basin in what’s known as the “bathtub effect.” So we’re left with a tight ball of roots crowded in a pocket of rich soil that’s considerably wetter (or drier) than the surrounding soil. Basically, we’re left with a rootbound potted plant! And an unhappy one, at that.
How to Amend Your Garden Soil
Nowadays, any conversation on this topic tends to dissolve into a hopeless argument between the “do-digs” and the “don’t-digs.” Some believe soil amendments are vital to growing healthy plants, while others believe that if it won’t grow in your native soil, you shouldn’t be planting it. But if you want to grow plants or vegetables, and your native soil is of poor quality, what’s a gardener to do?
Take the time to dig a large hole when planting shrubs.
To keep your plants happy, all it takes is a little more thought, and a little more digging. Follow these tips to help the plants in your garden grow:
- Choose Plants Wisely: Seek out plants that are well-suited to your native soil. For example, if your soil is clay, don’t try growing coastal plants that are suited for sandy soil. This simple shift will make gardening much easier and ensure that your plants are healthy long after those soil amendments rot away.
- Improve All Soil: If you’re going to amend your soil, try to amend all of it, rather than just improving the soil right around each plant. Raised beds are a great way to improve the soil for large-scale plantings, or you can till up an entire area and replace or amend all the soil. For annual and perennial beds and lawns, amend the soil about a foot deep.
- Dig Big Hole: For deeply planted trees and shrubs where all over amendment isn’t possible, dig the largest planting hole you can. I plant shrubs in a hole no less than three feet in diameter, and yes, that’s a lot of digging!
- Don’t Overdo Amendments: The biggest problem with soil amendment comes from the extreme difference in texture between the amended and native soil. Mix small amounts of amendments into a generous helping of native soil to keep the boundary from being so shocking to the plant roots.
- The Myth of Soil Amendments (Washington State University)
- Top-Dressing to Improve the Soil in Your Yard (article)
- Soil Evaluation (video)
I live in Pueblo West Co. and the soil here is very poor, some clay some shale and I want to amend it, I bought some bags of top soil and I also want to add some horse manure but Im not sure in what order to do that. I’ve already dug out about 8 -10 inches of the bad soil and now need to know which to add first……the top soil or the manure. Thank you for any help you can offer.
I read the article” How to Amend Soil Around Shrubs and Garden Plants” and realized that I planted a pear tree by removing the heavy clay in my yard and replacing it with Miracle Grow garden soil earlier this year, the exact way this article said NOT to. The tree is currently very healthy but I am now afraid I have doomed my great tree for a terrible future. My knee jerk reaction would be to dig up the tree again and do it right, but I that would probably just make the situation worse. Is there a way to fix this “bathtub effect” problem and save my tree?
I have the same problem as Allen, above, only it’s with a rose bush. I’ve already replaced a bush that died … it’s in a spot the homeowner insists on using for a rose bush, and I want to make it work any way I can. What’s the damage control for a plant that’s already in a hole full of ammended soil sitting in the middle of a desert of clay?? Dig it up? Dig ceramic or gypsum in slowly? Work on the surrounding soil? Help!!
We have terrible clay soil with embedded crumbled brick from the previous owners. I too planted a serviceberry tree a couple of years ago the way you should not do. Just like others posting here I was not sure what to do. But I had to do something because the serviceberry tree was not doing as well as it should. So I decided to amend the soil around the serviceberry tree in sections about one month apart. I have now done about 2/3 the way around the tree with another 1/3 left which I will do in a month’s time.
When I started digging it was unbelievable how bad the soil was past the old hole I originally dug. It was like cement and not a single worm anywhere. I took the soil right out up to the drip line of the tree, hoping that I won’t damage too many roots but close enough to minimize the heavy clay belt around the tree. I replaced it with 1/3 plain top soil, 1/3 potting soil and 1/3 composted sheep manure. Into this mixture I added back some of the clay soil I had removed. Perhaps not as much as this article suggests but we’ll see. I can always work in a bit more.
So I think if the soil is really bad that perhaps removing/amending soil in stages with time in between for rest might be a reasonable way to go? There’s risk for sure, but if the soil is really bad, then there’s an even bigger risk by doing nothing. It comes down to a judgement call. I am no expert by any stretch, but this is my 2-cent’s worth on this topic.
Did learn a lot reading about soil amendment. I also have the same problem of hard clay which is very difficult to dig out and some times mixed with hard rocks big and small. I am going to redig around old fruit trees and use a better soil to improve my fruit trees. I do appereciate Suzanne Kyle comments. I do everything to save and improve my trees.
How can I add soil amendment to trees that are already planted and some roots close to the surface. I have clay soil. I am afraid of digging around the trees because I might damage the roots. My trees also seem to be hit every year with brown spots that look like rust. I need to find a way to make them healthier.
I had a reputable local nursery plant a juniper tree early Spring 2018. They do guarantee it for 2 years. I live in the Ozarks and have very poorly draining soil, not red, but grey and heavy, with big red rocks from the owners decades ago. Water just sits on top of the soil or runs off it. I don’t know if they did any soil amendments when they planted the tree, but there is a “brim” around the base. The soil compacts and has run-off when it rains heavily, and dries to like concrete when dry. I noticed inner branches turning brown, called them, and they said it was probably due to heavy rain and heavy soil. Should we get the soil amended, and can we do it ourselves if the nursery won’t?
The Soil Science Society of America has some great information on this topic: “You can add amendments to soil anytime, but the best times for working it into an existing garden are in the spring before planting, and in the fall when putting the garden to bed,” it states.
That said, for tailored advice, we recommend inviting a Master Gardener to your home to inspect the area.
Master gardeners train on a range of topics so they can provide advice, at no charge, for people in their area.
I live in Central Cal where we have hard pan clay in parts of the county and sandy loam in other parts. On my own hobby farm (12 acres) I grew healthy apple trees, pomegranate, almonds, maple trees (for shade), all kinds of veggies, grapes, nectarine and some other fruits. We had hard pan clay. During rains we prepared the growing areas by roto-tilling the land as deep as we could then started adding compost (hoe made and cow manure after the rains and then added fish water, crushes egg shells, grey water from our kitchen sink. My tress, bushes, veggies, flowers were the best in miles around. From time to time I dug around large trees about 304 feet away from the trunks and added home-made compost, dry leaves, grass cutting fro my lawn etc. Also when I washed my fruits and veggies, rice etc I saved the water for my veggie garden and I never had to use pesticides. I had fixed soakers around all the fruit trees around where I dug. I never used store bought compost (that’s just me). We sold the land back in 2005 and I happened to drive that way what I saw was pathetic. Many are suffering, some are dead for lack of proper care. We have chlorine in our water so I had a whole-house water filter and so the trees got filtered water except for the apples (9.5 acres). Trees are living things and they need proper environment and care to produce. Now I live in the city and have 10K sq ft land with 2700 sq ft for house and garage. I have several tropical producing trees, olive tree, orange tree, peppercorn tree, three large shade trees and getting ready to plant more tropical trees and fruit trees in between that require watering only 1xweek all along the back wall which I have been preparing for over a year now. This fall my trees will go in which are in large pots. Even the trees that were slated to be taken down i was able to bring back to life and are blooming like crazy right now. I play classical music in my hoe and leave window open for trees to hear the calm soothing frequencies. No I’m not a tree hugger. Just a simple girl who grew up on a farm on an island in the Pacific and learned to grow plants and trees even on rocky grounds, from my parents hence my love for agriculture and horticulture. I also grow coastal plants in large clay pots around my home. This year many of those bloomed. I do check and fix pH balance of my soil and grow complimentary bushes/plants around trees. Thanks to God for the rain I can grow more plants. I like to continue learning and find your site informative.
Thanks for sharing your experience with the TodaysHomeowner.com community, Sindee!
Take care. 🙂