Is Garden Magic Top Soil suitable as soil (by itself)?

[Cicero_wnb]

I want to fill my newly built 4'x24' raised bed, over 1 ft deep, with a good soil to grow vegetables and herbs (and maybe some flowers too, why not). I purchased 5 40-lb bags of top soil, different brands, from local stores, and sent samples from each to our Extension Service for testing. Based on the results I got back, and also from price considerations, I will choose one named Garden Magic Top Soil, produced by Michigan Peat. Now that I'm looking more closely at this product, I noticed that instructions on the bag talk about using the product to "top your soil". Specific recommendations for using this product are:

-Top dresses lawns and gardens

-Patches bare spots on lawns

-Loosens heavy soils

-Improves moisture retention in existing soils

(this is verbatim from their web site)

Interestingly, there is no mention of using this product as your soil, period. It's always about doing something to your existing soil in order to improve it. So I called Michigan Peat and asked whether this particular product is suitable for use as the only soil (as opposed to something used to enrich existing soil). The person I spoke with seemed to be caught by surprise by my question, and after a few seconds of silence (and apparent hesitation), slowly said "yes, it should work". So the official answer from the company, technically speaking, was "yes", but I didn't feel exactly reassured. Perhaps it would help if I mention that they describe the composition of Magic Garden Top Soil as a "blend of dark reed sedge peat and sand". Not knowing anything about soil composition in general, this description doesn't help me much. I know it's supposed to be a mix of clay, silt, and sand, but how does "dark reed sedge peat" fit into this scheme? I know from the test results that the pH and mineral and organic content are all good, so one question to ask would be, is the structure of this product adequate?

I'd like to know if anybody happens to have used this product and knows whether it can be used as "real" soil (whatever that is). Any other related experiences or insights will be appreciated too!

[gregpresley]

[Salty Thumb]

[e-mail] (Cicero_wnb) wrote in news: [e-mail]:

If I recall correctly, it is suboptimal to grow stuff purely in "topsoil". Don't remember why though. Might have to do with drainage (you want a less permeable layer to slow water from siphoning below the root level but not so impermeable as to continually waterlog the roots) or nutrient intake (same idea, you don't want water soluable ions to wash beyond your root depth).

Topsoil belongs on top, subsoil on the bottom. Yes, topsoil is soil. According to your product's marketers, dark reed sedge peat is the primary organic component of their topsoil. I don't know enough about reed sedges to know if I should be impressed or not.

[Pen]

You're right to test them. I'm too cheap to do so. When I first began gardening, I got whatever was on sale. For annuals and perennials, I dug top soil into the hard clay down to 12". I had a triple mix that became crusty around mid-summer probably because of all the salts in the manure portion of the mix.

For shrubs, I simply dug as deep as I could get, usually 24", and filled it with top soil then planted my shrubs in the top soil. The shrubs did great for a couple of years then it would sink into the soil so I had to add more soil each year or take the shrub out and replant it. I'd don't know if I'm imagining it but the top soil in these pits seems to shrink.

Plants do beautifully in pure top soil. If your mix is light enough, you might want to try it as a potting mix for outdoor plants too.

[Cicero_wnb]

I can't argue from my own knowledge, but this seems to go counter to the general recommendation of "raised beds" and "deep soil". Do you really think that one foot of top soil is too much?

[Salty Thumb]

[e-mail] (Cicero_wnb) wrote in news: [e-mail]:

Warning: blind leading the blind here or at least visually impaired leading the blind.

I would say it depends on what you are growing. Aside from nutrient intake the roots have to hold the plants in place. Is your homogenous heap of topsoil going provide enough stability for that? Someone else said she had excellent results, and I can imagine that some plants would work really well in pure topsoil.

All I can say for sure is I once rooted a rosemary in pure topsoil (although it was in a gallon container) and it died, whereas the stuff in potting mix 90%+ survived. Looking back, this so called topsoil (el cheapo brand) probably didn't have much organic matter in it and crusted up like brick. I suppose if you make sure you have organic matter or add compost and have proper drainage, you should have excellent results.

[Warren]

So what is the official definition of "top soil". Is it like "top shelf" in liqueur -- the most expensive name brand? Or is it simply soil scrapped off the top of someplace?

Most of the stuff I've seen labeled as "top soil" is soil scraped off the top, with the biggest rocks screened out. Barely a step above "clean fill", but nowhere near what I would consider "top shelf", despite the higher price put on it because someone decided to call it "top soil".

Of course I'm answering my own question here. "Top soil" is stuff scrapped off the top. Mistaking the use of the word "top" in "top soil" to infer quality is a rookie mistake.

For that matter, "potting soil" simply means it'll fit in a pot if that's where you want to put it.

There are no official definitions of what soil labels mean. If it's a commercial bagged mix, the label may give you some idea of what has gone into that particular soil. You can judge drainage capabilities with some basic tactile tests involving water. But if more is important to you than drainage, you're just going to have to have the soil tested. Simple labels like "top" or "potting" won't tell you what the pH is, or what the NPK values are.