I had a recent soil test done on one section of my garden. I have had plants die in the past and recently the plants looked poorly in most of the area.
The test showed high levels of phosphorous, potassium and organic matter. The test does not test for nitrogen, but based upon my organic matter levels they didn’t recommend any added nitrogen. They did mention that, “Nitrogen is not listed because the level is not stable in the soil. It changes too frequently.”
What they recommended was to cut back on the compost, since my organic matter level is so high and to cut back on the phosphorous and potassium. He said that high levels can stop the uptake of other nutrients.
Their main recommendations were…
Just use a high nitrogen fertilizer without added phosphorous or potassium – blood meal, cottonseed meal etc.
Don’t add compost for a while. Try hardwood mulch on top
I did notice that added milorganite did green up the plants, but also adds phosphorous.
I noticed that Home Depot is carrying a number of Kellogg brand soil mixes, so I decided to buy all three and see what the difference is between them.
Raised Bed and Potting Mix – $8.27/2cu.ft. – This mix had 2.5 cups of large wood particles out of 12 cups. Other than that, it is similar to #3 – the Premium Potting Mix.
Garden Soil – This is not Top Soil. At $6.97, it is the cheapest, but is more like a nice mulch, not a soil for planting. it has 4 cups of large wood chips out of 12 cups. It does not contain perlite.
Potting Mix – Premium Mix for Outdoor Containers. This seems like a nice mix for use in a pot or in the garden. Out of 12 cups, it only had 1 cup of large wood chips and perlite. This is my favorite and at $6.47/1.5 cu.Ft., it seems like a good buy.
All three contain tiny amounts of fertilizer, so you will have to add your own fertilizer to these mixes.
Kellogg – All Natural Topper – a new product I just discovered. Unfortunately it contains 4 cups of large particles out of 12 cups. $6.27/1.5 cu. ft.
Here is another brand from Miracle Grow – Natures Care – organic raised bed soil. Unfortunately, it is about 40% wood particles. It would make a nice mulch. It has a little nutrition, but not much. It also doesn’t have perlite.
After watching a couple of years of Monty Don on “Gardeners’ World,” one of the differences I noticed was he doesn’t use peat moss in the U.K. He mainly uses a lot of compost, perlite and grit. I’ve also never seen him use fertilizer other than compost which he makes himself.
You would be hard pressed to find this mixture in any nursery or big box store.
What I have found is a mix which seems similar to what Monty Don uses.
SLC Grower’s Mix has a combination of pine bark fines, compost and PBH rice hulls, although they wouldn’t tell me the exact percentages.
When I talked to SLC they did indicate that they would recommend using Osmocote if I was planning to grow from small size to large size in a pot. He recommended using a medium dosage. They do include a small starter nutrition in the mix and a micro-nutrient charge.
The product will be a bit drier since it drains so well. You may have to water more often.
I’m going to be doing some tests with this product versus my standard BX ProMix. The SLC mix is only $6 per 2 cu. ft. bag.
You would obviously be better off buying the mix in bulk, if you have a place to dump it.
The one odd thing about this mix is that it is in bags which say Cotton Blossom Compost.
I was recently asked how to plant in clay soil.
Here are some options.
First off, kill off the grass and weeds. You can cover the area with a tarp or newspaper/cardboard or use a herbicide. Use a lawn mower with a bagger and remove all the weed seeds and waste. You don’t want to have to battle the weeds during that first year.
The easy way to plant with a clay soil base is to cover the area with 6 to 12 inches of a good soil/compost mix. You plant in the soil mix and not the clay soil. Over time, the roots and earthworms will break up the clay soil.
Another option is to plant native seeds in the fall. Make sure the seeds come in contact with the soil. The above are Asclepias tuberosa seeds I planted last fall. I then cover the seeds with a soil mix so that the seeds are covered and will germinate easily in the spring. Native plants don’t need or want good soil for growing.
If you have the time, energy and money, you can dump lots of compost onto the clay and till it in. You can then plant directly into the soil. Unfortunately, in the process of roto-tilling you will bring up dormant weed seeds and will have to battle the weeds in the spring.
The final option is to make a hole for each plant and throw away the clay soil. You can then add a potting mix to the hole when you plant. I have used a large bulb planter in the past with this technique and it works well.
When the plants are growing well, you can add mulch to help with the weeds and conserve water. I usually add a mixture of compost and mulch every year to help feed the plants and improve the soil. Note – I found out that the mixture I got was very hot and killed most of my grass in the center.