Extreme Makeover For Your Soil
by Jack Shoultz
This article is an Award of Merit winner for 2006. It originally appeared in "The Budding Rose Gazette."
Of all the conditions that help make your roses grow and produce the way you want them to, one of the most important, if not the most important, is the soil you put them in. Of course, if we were able to talk about perfect conditions, the top layer of soil would not have been scraped off and hauled away when preparing your area for building your home. If you look at new housing developments going up you can see how they level off the areas and that was the best part of the soil. And when the bulldozers leave, they leave you with the problem of poor soil. Before planting anything, ideally, you would start preparing the soil a year ahead of time. But, that will rarely be the situation. Most of us are not that lucky or don't plan that far enough ahead. There are things you can do to improve your soil after you have put in a rose garden if you don't take the time or have the foresight to get it done earlier.
Let's start out with the best of intentions. Before I start that, I will say that I have never taken a sample of soil in to a lab to have the pH checked or see what the nutrient content of the soil consists of. (If you have a continuous problem with all your plants then it may be a pH problem that you may need to address by getting the exact pH of your soil, so you will know how to best correct the situation.) I start out trying to figure out what type of soil texture I have. Dig out a sample of soil from 6 inches deep and add water to it (do this in more then one area). If it sticks together with no crumbling then more than likely it is clay. This is very simplistic, but will give you a starting point. You can also use a "soil sampling tube" for taking samples by simply pushing the tube into the ground to the point you want to check, twist it and pull it out. The sample of soil will show the moisture retention. If the sample is damp in the area checked then there is correct moisture for that area. If the soil is soggy and has a foul odor then it is holding to much water. A soil that appears dry is unlikely to be appropriate for roses.
But whatever type your soil, many methods of improvements will help. If you have tried to grow plants in this area before and had difficulties then how those plants reacted could give you clues to the problems within the soil. If this is a new area that you are either changing from a lawn or just has been fallow, once the top growth is removed, then the next decision you make is if you are going to utilize the entire area or just dig holes to plant in. If you have the time, it is best to prepare the entire area. At this point, and only at this point, would I recommend rototilling the area. The problem with rototilling soil is that it packs the soil by removing air. Hand digging is a better option, but if it is a large area, may not be the best solution. There is a technique called "double digging" that is very effective. Do this when the soil is moist, but not very wet or dry. You just start by digging a trench, throwing the soil in a wheelbarrow or on a tarp. Then dig on the side next to the trench and put that in the first trench. After digging the first trench (and before filling it with dirt from the second trench), it is a good time to put some amendments in the bottom and loosen the soil to mix it. Continue digging, amending, and filling in the trenches as you go and with the final trench, put the original soil from the wheelbarrow. The double digging methods works very well in areas that have been worked before. Using a rototiller is faster and not as hard on your back. Preparing your soil properly in the beginning may be more work and take a lot longer than just digging a hole, but pays permanent dividends.
Another good option is raised beds. These can be anything from cosmetically esthetic stones or just using timbers. Raised beds make the problems we have in the soil a nonissue. Even a bed of 12 inches deep will work and will eventually make the soil below as rich as that in the bed, as long as you continue adding amendments which help improve the soil. A raised bed can be the best of all worlds if you put in a high quality soil of your choice.
The majority of large roses do much better planted in the ground as opposed to containers. For those roses decide what amendments you need for your soil. There are many alternatives and one of the ways to find out what works is to ask friends and neighbors whose roses look like you want your roses to look. Looking at some alternatives:
1) Compost - If you have the capabilities and the space, making your own compost is cost effective and self gratifying. Some gardeners try shortcuts with compost by putting it directly in the soil. This of course is fine if you are not going to use the area for 3-4 months. Organic material put in the soil before it is composted will require nitrogen as it breaks down and therefore if you put it in an established rose bed it will rob the roots of your roses of needed nutrients. Nitrogen from decaying organic material is not readily available to plants. First, it must be converted by the bacteria and fungi in the soil to ammonia, then nitrites, and finally into nitrates that can then be utilized by the roots. Completed compost contains nutrients that are available and will not cause any nitrogen depletion. There are commercial forms of compost and many of them are very good, but nothing compares with the homemade stuff.
When looking for commercial compost, check the list of amendments. If there is a lot of wood products in the mixture, it will break down and the actual quantity will reduce as it breaks down over time. Wood products introduced into soil are very good at opening up and adding aeration as it breaks down, but as with all products, will need to be renewed to keep the soil from reverting back to its original structure. The smaller the components the easier and quicker the process.
2) Amendments - can be anything that will add both air and provide water-retention. Examples are perlite and vermiculite which can be fairly permanent, breaking down very slowly. Commercial products can have these as part of their structure such as Gro- Mulch and other products. When adding these to the soil, it is best to add 25-50% of the total soil volume as you cultivate the area. As mentioned before digging is preferred over rototilling. Mixing in the amendment will help keep the air in the soil.
Some problems you may have in the soil:
- Alkaline or Salty soils. Both usually occur where there is very little rain. Alkalinity can be lessened by liberal watering. Salinity is an excess of salts which can come from local water, fertilizers or chemical products, and manures which may have high salt content. The salts need to be leached from the soil. There are products that will help flush the salts out of the soil if there is not enough rain or you do not deeply irrigate.
- Plants not getting proper nutrition. If your plants are not prospering, and the soil drains properly and you are watering properly so that your soil retains moisture, the problem is probably a lack of nutrition in your soil. It may need a quick fix of a complete fertilizer, but especially nitrogen, phosphorus, and potassium. A soil that is compact may not allow the nutrients in the soil to become available to the rose roots. It is the time to start "fixing" the soil by starting to build it up with amendments. Soil amendments that improve aeration and water penetration will also improve the soil's ability to make the nutrients available.
- Lack of iron. If the symptoms of leaves being yellow between the veins, then use a chelated iron which gets to the plants quickly. Follow directions closely and do not overfeed. If you have treated your soil as is described above then your garden will be beautiful. If not, then figure out what is missing and make the appropriate changes to bring your soil up to the best it can be.
Once you have achieved the proper soil, don't forget to maintain it. It becomes much easier and less work over time. The results will be worth the work and your roses will thank you for making it easy for them to be the best they can.