Many of us are experiencing a change in our daily lives that keeps us at home more than usual. Combine that with concern over food safety and the fact that we are in spring, the perfect time for new gardens, and you’ll understand why seed and plant companies are being inundated with new customers.
New customers mean new gardens and that has people wondering about what they should do to make their soil “healthy.”
A trip to your nearby garden nursery will reveal dozens of soil amendments being marketed these days. All of them promise improved “soil health” and increased yield from whatever you are growing. But will you get the spectacular results claimed by some of these products?
Chances are the answer is no, you don’t need to overhaul the soil. In most cases your best bet is to add a modest amount of composed organic material and leave it at that. This will loosen compacted soil, improve water retention, and provide a slow-release long term supply of nutrients. You can’t get any better than that.
So what about all those designer soil amendments on the market? What shows up in your neighborhood nursery varies considerably depending on where you live. Here’s a quick rundown of some of the more popular amendments.
Kelp Products – If It’s Local
Composted sea kelp products are available in some coastal areas. Kelp can be used as an amendment but it doesn’t bring anything special to the soil. Better to use composted green waste from local sources than a designer amendment shipped in long distance.
Peat Moss – Definitely Not
This amendment became popular in the first half of the 20th century. It was originally prescribed for almost any soil, regardless of the problem. Peat moss is fine for lining wire hanging baskets and covering soil in containers but is no longer recommended by garden expert. There are also some concerns about the ability to sustainably harvest this resource.
Epsom Salts – No!
This darling ingredient of many home-brew fertilizers shows up all the time on the internet. Epsom salts provide magnesium and sulphur, two trace elements important in healthy plant growth BUT these are rarely absent in soils. Unless a chemical analysis of your soil shows low amounts there’s no reason to add this. In fact I’d go so far as to say an application of Epsom salts can be harmful to otherwise healthy plants.
Mineral Supplements – Maybe
There are times when garden soil is indeed deficient in key trace elements. This is when gypsum, lime, bone meal, blood meal, other mineral additives can help. However you should be sure your soil actually needs these additives. The only way to tell is by a chemical analysis (soil test) of your garden. Just because your neighbor down the way spreads it on his garden doesn’t mean it’s worth adding to yours.
Perlite and Vermiculite – Containers Only
These two additives are most commonly used in potting soil where they help to keep the soil light and provide space for air. Both are made from raw minerals that are superheated until they expand explosively like a popcorn kernel. Because they come from chemically inert rock they are safe to add to soil. However they are relative expensive and, frankly, don’t bring significant benefits to your garden beds. Better to spend your money on organic composted materials.
Hydrogels – Meh
These are white crystals that absorb water when they are added to soil, expand to many times their original size, and then slowly release the water back to the soil. This has been touted as the new wonder additive to potting and garden soil, especially for those in hot climates.
However tests have shown it doesn’t provide significant long term benefit to the health of the plant, even in container gardens where one would think it might have the most benefit. Furthermore, high temperatures, tilling, and ultraviolet radiation all work to break down hydrogels, leaving you back where you started in a season or two.
What You Really Need
The bottom line on soil amendments is that, dollar for dollar, nothing beats regular application of composted organic material. It does everything you want (improved soil texture, better water retention, and safe, slow fertilization) with no negative side effects. Who could ask for anything more?