GardenLine

GardenLine

Skip Richter, based in Houston, is a popular speaker for garden clubs, Master Gardener programs, and other gardening events across Texas. He has...Full Bio

 

The real dirt on why you should avoid peat in your landscape

This week’s GardenLine tip is on the subject of peat moss, including sphagnum peat moss, and why you should avoid it in Southeast Texas landscape beds. It’s an overview of material I’ve compiled from other landscape experts, including Mary Cummings, formerly of RCW Nurseries and now at The Grower’s Outlet, and Linda Gay of The Arbor Gate, formerly director of the Mercer Arboretum.

“Organic” garden soils or raised-bed soils derived from sphagnum peat moss and processed forest products have GREAT water-holding abilities – they act like a sponge. Their jobs are to hold moisture in the soil around plant roots. But when soil stays wet and cannot dry out, plants cannot produce food sugars. They essentially drown.

On the other hand, when peat-heavy soils dry out too much, as often happens when it is used as mulch, an impenetrable barrier forms, so water cannot percolate down to root systems. I often see this in my consulting business. In fact, here’s a bag of the stuff I found during a recent consultation that was being used in West Houston. Note that two of the top three ingredients are peat-based.

The use of peat is also environmentally unsound. Peat moss is the partially decomposed remains of sphagnum moss, and it's harvested from delicately balanced bogs. As Mary Cummings has written “…the biggest problem with peat moss is that it's environmentally bankrupt! It is essentially ‘mined’ by scraping off a bog's top layer of living sphagnum moss. Despite manufacturers' claims that bogs are easy to restore, the delicate community of animals and insects that inhabit a bog cannot be quickly re-established. Yes, peat moss is a renewable resource, but it can take hundreds to thousands of years to form.”

Here’s my simple rule: If the first two or three ingredients listed on a bag of soil are peat moss or sphagnum peat moss, avoid it in landscaping. You and I alone may not be able to change the environmental degradation resulting from peat bog harvesting, but if more of us use peat-free products, like those I endorse, it may have an impact.

Peat is not the amendment needed to improve clay soils. We need to add more compost and shale. Why shale or small rocks? To create pore space. Here’s a great explanation from Linda Gay: “ I had a female customer who asked how she could convince her husband to buy rock and work it into the soil, and I told her the soil has COPD (Chronic Obstructive Pulmonary Disorder) and the rock will open up airways for the plant to breathe. She totally understood that analogy.”

We cannot see soil air spaces, just as we cannot see inside our lungs. We can only see if plants do well or not.If your plant hasn’t grown 2 inches in 2 years, there may be no spaces for water to reach the roots. The roots don’t grow, so the plant just sits, then declines. Add permanent amendments like expanded shale - porous pebbles – that “breathe” with the plants.

In this region, we garden in heavy clay soils or small particle sands, so every time we put a shovel in the ground, we need to add compost and expanded shale to create more air spaces. And you only get one chance to get the planting right. Start with quality rose soil at the very least. It does contain humus or compost, but the ones I recommend don’t include any peat.

The Arbor Gate has a proprietary soil blend called Organic Soil Complete. It’s “complete” because it features every component needed to grow thriving plants in our clay soils. Key among them are compost and large-particle sand, both of which encourage really big root systems that need minimal watering and daily care. The blend also includes expanded shale - permanent porous pebbles that “receive” and “release” air and water as they get wet and dry out.

For the record, there are a few products I endorse that have some peat moss in them. But it amounts to only about 10% of the whole product. And I don’t recommend those products for landscape beds - just potted plants, hanging baskets, and maybe some raised vegetable and herb beds.

By the way, I have previously published tip sheets suggesting that peat moss helps control Take All Patch in lawns. While that advice may have been considered helpful 20 years ago, today we know that vegetative compost (leaf-mold compost, double-screened compost, etc.) are better spreadable cure-alls for fungal issues in turf. Besides, I don’t think anyone, anywhere, these days could even find a “peat spreader.”


Sponsored Content

Sponsored Content