Amendments

November/December 2015

My house is built on five feet of what is called fill dirt.  The dirt is compact, lifeless and very difficult to dig into.  I would like to plant some ornamental trees next to the house. In particular I would like an ornamental cherry.  My guess is I would have to dig a huge hole and fill in with good soil.  I am worried what will happen when the roots eventually try to move out and hit the wall of fill.  Will the tree die? Is there anything I can do or are there plants that like fill dirt?

Keep in mind that the foundation to a garden is its soil.  If you have poor soil, then amending it will help.  You do not want to dig a hole and throw away the fill and backfill with good soil.  You want to work with the pitiful stuff you have and amend it and make the soil as homogenous in as large an area as possible. If you have a blank slate—nothing is planted yet, then bring in a load of compost and till it in with the fill.  Sometimes the soil gets so compacted after construction that running an aerator over the area can help.  Compost can work wonders in lightening up heavy soils and adding some organic matter.  When planting, try to amend at least three times as wide as the planting hole to help in root spread. The key is the wider the  area can be amended, the better. Roots spread outward much more quickly than they grow deep.  But mix in your amendments, don’t totally discard what you have.  If you throw away what you have and plant in good soil, you are basically containerizing the plant in the ground. The roots will stay in one spot, and water flow will vary based on soil type.  Good luck.  Over time, you can create great soil.  

October 2012

I am writing to see if you can give me some tips on blueberry cultivation. I've had these bushes for four years and I keep losing one or two each year. I have watered and fertilized in the spring, then used Miracle Grow throughout the summer. Still, they keep dying on the tips and then I soon have a whole branch that is gone. Then the plant dies. These are within easy reach of the hose and I have installed drip irrigation. I had a soil test in January, 2011 which revealed a soil ph of 7.2. I added 10 pounds of sulfur per 1,000 square feet to acidify the soil. They are also mulched with pine needles. They have a few berries but last year the birds wiped them out.

I think you have a couple of issues. First of all, blueberries need a well drained, acidic soil. From the pictures you sent me, I think they should be planted a bit higher with mounds of soil and mulch—basically a raised row of soil. This ensures good drainage. While they like ample moisture, they can’t tolerate wet feet. pH is also critical. They need a very acidic soil around 5-5.5. 7.2 could cause them to die. The last picture showed some pretty yellow leaves with green veins—a sure sign that the pH is too high. The plants can’t absorb the nutrients in the soil if the pH is not in the proper range, which can cause the iron chlorosis you are experiencing. Get the pH in range, and mound up the plantings. Drip irrigation is great. When you lose a plant and dig it up, does it have any roots left, or have they rotted? Mulching with pine needles is great, but make sure the plants aren’t staying too wet and that you don’t have them planted too deep.

December 2010

I have cleared some land that is extreme clay. I have sand left over from a building project. If I spread the sand on the soil will it make any difference in the clay?

Sand and clay make concrete. Try adding compost to the clay to lighten it without the compaction issues. Shredded leaves also could be worked in this fall. A little sand mixed in with the compost would be ok, but don’t just do sand and clay.

October 2010

I live in a part of Arkansas that allows me to burn leaves. I do so regularly and I also recently burned a wood pile. Can I use some of these ashes on my flower beds and on my garden plot? If so how much would be advisable?

A little bit goes a long way. Wood ashes tend to raise the pH of the soil, so don’t use them around acid loving plants and don’t add additional applications of lime to the soil if you are using them. Ash also contains salt, so large amounts would not be beneficial to a garden. Composting the ashes along with leaves and other raw materials can help to dissipate the salt issues for later use, but have it tested to determine pH before using. Therefore, when using wood ash, a light layer is all that is needed. Avoid using it around azaleas, blueberries and other acidic lovers, and don’t use it in your vegetable garden where you grow potatoes, or you may have potato scab—which occurs when you raise the pH.

October 2007

What is the recommended rate of nitrogen per 1,000 square feet per year for annual color beds?

When we talk about fertilizing annuals, we usually want to use a complete fertilizer as opposed to a nitrogen only fertilizer. With the huge range of fertilizers that are on the market, and the various forms—granular, slow release, water soluble, etc., it is best to find a product you like and follow the label directions. I like to start the season with a slow release product (often 20-20-20) and follow that up with regular applications of a water soluble form. The key with annuals is to push them as much as possible to get the most flowers.

November 2009

I'm new to Arkansas and have bought some acreage north of Batesville. It includes bottomland and a raised meadow (the grassy knoll) which I fear is a huge gravel pile covered with a little topsoil. Don't know that, but I fear it. When I dig, I immediately hit marble sized rocks. I have mail ordered some pecan and chestnut trees. Both say plant in well drained, moist soil. I'm guessing that the grassy knoll will drain well, but I don't know if it is suitable for my nut trees. By the way, the adjoining land is covered in cedar and oak trees. What do you think?

Just looking at soil and the lay of the land, really doesn't indicate internal soil drainage. You need to dig a hole as deep as you plan to plant your trees then fill it with water until the water stands. See how long before the water drains. That should give you an indication of drainage. Planting, much less digging, and then growing can be a challenge in extremely rocky soil, but much of Arkansas is in the same boat, and we have lots of plants, so it is doable. Get a soil test, test for drainage and see if you can amend the soil in an area at least three times the width of the planting hole with compost, incorporating that with the existing soil. Give your pecan trees plenty of room to grow, since they are large trees at maturity.

January 2010

In the spring of 2007, I planted fourteen arborvitae trees around an air-conditioning tower as a screen. The soil is mostly clay. I dug planting holes twice as deep as the root ball, and added quite a bit of compost both under, around, and on top. That first summer I watered them religiously and they did fine. The next summer, 2008 was fairly wet and so I was not regular in watering them. One after another they began dying. I was surprised when I pulled up one of those that had died to find that the roots had not grown at all, out from the original root ball. Three have survived until now. Is there some secret to growing these trees? Is our area not suited to them? Does one have to pamper them for several years? Why didn't the roots show any growth? I do not want to try replanting around the AC unit unless I could hope for better success.

I think there may be several factors at work here. First of all arborvitae plants are fairly drought tolerant once they are established--too much water would be worse than dry conditions. While they like water, the soil needs to drain well. Clay soil is not known for its friability. It holds water far better than most soils, so this could be a factor. Was the soil gray in color or have a sour smell when you dug them up? The fact that your roots didn't spread at all tells me a few things. Root rot could be a factor from too much water, but if the root ball was not disturbed at planting and the plants were root-bound, then they stayed that way in the ground--and were not able to take up nutrients and water any further away than there were roots. Planting too deep can also hurt them--we normally want the crown at the soil level, or the plants can smother. Amending the soil is fine, as long as the compost or amendments are mixed in with existing soil and the amending is two to three times as WIDE not Deep as the planting hole. Roots don't typically grow down very far, but they should spread far and wide, that is why we want to amend in a distance away from the plants. If you can't amend a wide area, then don't amend at all. Otherwise, you are basically containerizing the plants in the ground

December 2008

I recently burned a wood pile. Can I use some of these ashes on my flower beds and on my garden plot? If so how much would be advisable?

Actually, wood ashes can be a source of potassium and calcium, but should be used sparingly. They will raise the pH of the soil and can also add to the salt content. Definitely don't use them around acid loving plants like azaleas and gardenias, or blueberries or potatoes. A light scattering won't hurt in a vegetable garden, but a little goes a long way. You can compost a small amount as well, layering them between your raw material, but again it acts similarly to lime and can raise the pH. If you use wood ashes, don’t use lime as well.

May 2007

My husband smokes meat with a smoker and uses the regular charcoal. We were thinking we heard you could re-use the ashes from the charcoal in a garden. Is this true? And if so, what type plants can we use it with? I have gardenias, azaleas and irises in our yard.

Wood ashes can be used sparingly, and charcoal ashes should not be used at all. The process in making the charcoal and then those which have chemicals added to aid in getting the fire started are not beneficial to most plants. Ashes tend to have a high salt content overall and also raise the soil pH, so if using any ashes at all, use only small amounts. Do not use them at all around acid loving plants like gardenias and azaleas.

All links to external sites open in a new window. You may return to the University of Arkansas System Division of Agriculture web site by closing this window when you are finished. We do not guarantee the accuracy of the information, or the accessibility for people with disabilities listed at any external site.

Links to commercial sites are provided for information and convenience only. Inclusion of sites does not imply University of Arkansas System Division of Agriculture's approval of their product or service to the exclusion of others that may be similar, nor does it guarantee or warrant the standard of the products or service offered.

The mention of any commercial product in this web site does not imply its endorsement by the University of Arkansas System Division of Agriculture over other products not named, nor does the omission imply that they are not satisfactory.