How to Use Peat Moss Wisely

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Question. Dear Mike: How do you feel about using peat moss as a mulch? And is there a rosebush without thorns? Thanks!

---Hank in Wilmington, Delaware

Answer. Not completely without thorns, Hank; but some rose varieties are said to have very few, including the legendary "Climbing Cecile Brunner", a light pink, repeat blooming old garden rose. The noted German breeder Kordes has a dozen 'thorn-less' varieties in their "Satin Touch" line; and another dozen are available under the "Smooth Touch" brand from Australia—all of which have the word Smooth in their name (like me).

Anyway, don't use peat moss to mulch them roses. Yes, the low price per cubic foot of material makes using the contents of those giant bales for mulch an attractive thought. And yes, mulching is listed as a potential use on some of the wrappers. (Heck—the big bale I have out back says you can use it as a breakfast cereal in a pinch.) But peat moss is not the wisest choice for a mulch.

First and most important, peat moss is highly acidic, and using it as a mulch around non-acid loving plants could greatly stress them. It also has a tendency to form unsightly surface cracks when it dries out; and it's too light to stay in place when faced with high winds and rains. (In fact, its so naturally dry and dusty it would be difficult to apply as a mulch on anything other than a 100% wind-free day.) And it doesn't convey much (or any) actual nutrition to plants, the way other organic mulches do.

But I know where you're coming from; you get soooo much of it for so little money; and every garden center has it. Would that packaged compost were so common! Anyway, stick with the good mulches: Compost, pine straw, dried clippings from herbicide-free lawns, shredded fall leaves and cocoa bean and other seed and nut hulls and shells.

And of course, stay away from wood, bark, root and rubber mulches. I'd go for peat moss neutralized with some wood ash or lime before I'd use any of those bad boys.

Question. Mike: What is your opinion on using peat moss as a soil amendment? I have read conflicting stories. Also, can it be composted with my shredded leaves and grass?

---Lisa in Dothan, AL

Answer. It can be very useful, Lisa. But as we just warned Hank The Rose Thorn Scaredy-Cat, you have to know what you're doing. You don't want to mix lots of peat moss into your soil willy-nilly any more than wood ash. Because just as the wood ash can make your soil too alkaline, peat moss can make it too acidic; especially if you live in an area where the soil is already acidic. We'll go into detail about using it safely in a minute.

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Question. I'm writing this as I get ready to plant my tomatoes, eggplants and peppers, and I wonder if the addition of peat moss to my soil would change the pH in a detrimental way. I have spent the past three years conditioning the soil with compost, but the dirt doesn't seem to be deep enough yet. Would the addition of peat help or hurt? Thanks,

---Danielle in Butler, TN

Answer. Alone and un-amended, it could well hurt, Danielle. Have a soil test done. If, like our friends in Oklahoma and the Far West, your soil is naturally alkaline, adding peat moss would both bulk up your beds and improve the pH. But if your soil is already acidic (as it is for most of us in the North), it would be a very bad idea.

If you have a lot of peat moss handy, consider following Mel Bartholomew's Square Foot Garden Plan. Create raised beds and fill them with lots of compost, peat, perlite and vermiculite; essentially creating a giant outdoor container that drains exceptionally well and can support a lot of plants. If necessary, add some wood ash or lime to the mix to level out the pH. And wear a dust mask! All of those ingredients besides the compost are very dusty.

Question. A friend gave us several large bales of compressed peat moss and I am wondering what to do with it. What do you think? Thanks,

---Barb in Maple City, MI

Answer. I think it's time for me to finally answer this question, Barb! My favorite use is to spread some peat an inch or two thick around the base of my acid-loving plants like rhododendrons and azaleas, and then cover that with an inch of compost. It keeps their soil rich and acidic just the way they like it.

For blueberries, which require a HIGHLY acidic soil, I first plant the things in half compost/half peat moss (a pretty good replication of their natural habitat) and then mulch them with lots more peat moss covered with some compost every season.

I also use peat moss to make my pink hydrangeas turn blue. And I combine equal amounts of peat, perlite, vermiculite and compost to make a perfect container/seed-starting mix, always making sure to add some wood ash to counteract the acidity of the peat; a couple tablespoons of ash for a big container; about a quarter cup to sweeten up a wheelbarrow load.

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