It’s a wonderful feeling to start your own garden.
You might have a big yard where you can create some raised beds. Or maybe you have a small apartment and want to try some container gardening.
The most important thing you need for your plants is the potting soil that you use. It has to be sterile, retain moisture without excess, and stay aerated.
You can’t just use garden soil for this. You need something better.
That’s where peat moss is an option to consider. Mixed with materials like vermiculite, perlite, and compost, it can make for some great potting mix.
What is peat moss?
Consumer-grade peat moss is dark brown plant material, fibrous and crumbly. It’s the decayed remains of live sphagnum moss.
Peat moss and sphagnum moss differ in texture. Whereas peat moss is chopped, sphagnum fibers are fuzzy and long. Florists dress up potted plants by covering their topsoil with sphagnum.
Where is sphagnum moss naturally found?
Sphagnum moss lives in peat bogs, native to cool and rainy geographic regions. Primary sources are Canada, Scotland, Finland, Russia, and New Zealand.
A peat bog is a type of wetland, a low-lying, flooded landmass, containing saturated soils and aquatic plants. Originally, peat bogs evolved from lakes. Over thousands of years, sphagnum moss overgrew the lakes. As the surface vegetation thickened, the lower layers gradually died and decomposed, leaving brown, spongy peat.
To this day, the cycle of moss growth and decay continues. Live sphagnum floats above the dead peat, ranging up to 10 feet in depth. Peat bogs are also called peatlands.
What are the gardening benefits of peat moss?
Peat moss is free of weed seeds and pathogens. Since it hinders the growth of plant fungus, it wards off root disease.
The fibers help the soil retain and release water. For this reason, peat moss balances sandy soil nicely. Sand quickly drains water from plant roots before they get a chance to drink. However, plants can easily draw water from peat, along with soil nutrients.
Peat moss prevents soil compaction. In dense soils, the particles are jammed together, making it hard for plant roots to breathe, drink, and grow. However, since peat moss is spongy, it loosens tight soils, such as those high in clay. As a result, air and water can circulate better, making roots less prone to rot and stunting.
pH measures the acidity or alkalinity of a substance, based on its hydrogen ion concentration.
The pH scale ranges from 0 to 14. A high quantity of hydrogen ions means the soil is acidic, being least acid approaching 7. Low hydrogen ions indicate an alkaline soil with a pH between 7 and 14. A neutral pH is 7.
Many food plants prefer soil with a pH of 5.5 to 6.5, at which they absorb nutrients best. The pH of peat moss is 3.5 to 4.5. Adding peat to an alkaline soil changes it to an acidic state.
Are there any drawbacks to using peat moss?
Peat moss doesn’t add much nutritional value to soil. Accordingly, you must fertilize plants regularly.
Although the price of peat moss varies, using large quantities gets expensive.
Is peat moss sustainable?
Peat mining is controversial. Environmental watchdog organizations say that peat moss isn’t sustainable. However, harvesters maintain that it is renewable.
So, let me simply present the facts concerning peat production. This way, you can make an informed decision on whether to use peat for gardening.
Peat moss sits well below live sphagnum. To reach the decayed material, harvesters must remove the sphagnum covering it. Then, they drain the bog and suction the peat with vacuum-type equipment. After harvesting, peat moss is dried, shredded, and chopped for consumer use.
Peatlands absorb carbon dioxide from the Earth’s atmosphere, markedly reducing air pollution. The live sphagnum presses against the peat below it, preventing carbon dioxide from escaping the bog. However, peat mining exposes the stored carbon dioxide, releasing it back into the atmosphere.
The annual rate of sphagnum growth is barely measurable — less than one millimeter or about 1/16 inch per year. For a bog to naturally generate one meter of peat moss, it can take 100 years. However, peat harvesters have discovered ways to expedite moss regeneration.
To save bog ecosystems from extinction, government agencies regulate peat mining. For example, Canada limits extraction to .016 percent of its bog reserves. Canadian harvesters can only access one in 6,000 acres at any given time.
For the last 12 years, Canadian peat producers have employed a new practice to facilitate bog restoration. This entails letting the wetlands re-flood and planting moss grafts. As the sphagnum grows, its top layer is replenished within five years. Restoring ecological balance can take 15 to 25 years.
Can I still use peat while promoting bog ecology?
Yes, in two ways. One is using small quantities of peat. For example, mix it with potting soil for seed starting or container gardening.
To support bog recovery, only buy Canadian peat moss from producers who are members of the Canadian Sphagnum Peat Moss Association (CSPMA). One such company is Sun Gro Horticulture.
For companies to retain membership, they must adhere to the CSPMA reclamation policy, mandating that harvesters:
- use mining techniques that speed bog recovery
- leave sphagnum in a viable state after harvesting
- ensure that at least three feet of peat remains at wetland bottoms
- earmark peatlands that must be left virgin
So, how can you know if a peat miner is a CSPMA member? One way is reading product labels. Another is visiting a retail website if a producer has one.
You can check if the company is present on this CSPMA membership list.
How is peat moss used in gardening?
To start plants from seed, consider buying peat pots. Once the seedlings have sturdy stems and leaves, put the containers directly in your garden. Be sure to cover the rims completely with soil. Otherwise, the peat will draw moisture from the seedling roots and surrounding earth.
Alternatively, mix your own seed medium. One way is combining peat and equal parts vermiculite and perlite, volcanic materials that aerate and drain soil. For this purpose, buy fine-textured peat, encouraging the growth of roots and tender shoots. Here’s detailed information on using peat to start seedlings.
Garden Soil Amendment
If your soil is high in sand or clay, adding peat will make it suitable for your crops. To do this, spread peat moss over your plot in a 3-inch layer. Then, mix it to a 12-inch depth until evenly distributed.
In a wheelbarrow, measure out two parts of soil and one part peat moss. Thoroughly combine and spread over the raised bed. Then, mix to a 12-inch depth.
If you’d like to add compost or commercial manure to raised beds, mix equal parts soil, peat, and your third amendment in a wheelbarrow. Then, add to the beds, digging to a 1-foot depth.
For each container, combine equal parts potting soil, peat, and compost, mixing thoroughly.
How to prepare peat moss for use?
Note that you cannot use peat moss dry, as it will repel water. Therefore, wet it well beforehand. To do this, pour the amount you need in a wheelbarrow or large bucket.
Add a small volume of water, stir, and allow the peat to soak. Repeat this process until the peak moss is thoroughly wet.
To gauge appropriate wetness, take a handful of peat moss and squeeze it. If this yields a drop or two of water, that’s perfect. If squeezing produces a water stream, add more peat moss until it passes the moisture test.
Where can you buy peat moss?
The material is widely available, sold by garden centers, plant nurseries, home improvement stores, and online. It’s marketed as both peat moss and sphagnum peat moss.
Quantities vary from quart-sized bags to bales, measured in cubic feet. Although peat is expensive, if you buy it in bulk, you may save money.
You’ll easily find organic peat. You may come across coco-peat, but this is another name for coconut fiber. Don’t make the mistake of buying sphagnum moss or spag moss, which are too coarse for gardening.
What are some alternatives to peat moss?
Ideal peat moss substitutes are compost, coconut fiber, PittMoss, and worm castings.
This is organic material degraded by the action of moisture, oxygen, bacteria, and heat. Like peat moss, compost helps the soil retain water. It’s a rich source of plant nutrients.
Compost is made from brown sources of carbon and green sources of nitrogen, combined in a 1:1 ratio. Ideal donors are dead leaves, grass cuttings, and food scraps, such as eggshells, fruit and vegetable peels, stale bread, and coffee grounds.
Since you’re new to gardening, I don’t recommend making compost from scratch. Instead, cut corners and buy from a garden center.
This material, also known as coir, comes from coconut husks. It’s sourced from the pulp around coconut fibers.
Coir resembles peat in sterility, fungal resistance, water retention, and appearance. Its texture is fluffy and light.
Furthermore, coir supplies plants with minerals. Coir also differs from peat by being denser, costlier, and less acidic. Its pH ranges between 6.0 and 6.7, close to neutral.
Another plus is that coir is sustainable. Coconuts grow year-round, maturing every two months.
Coconut fiber comes in several forms — granules, pots, sheets, bricks, and bales. Whatever the type, you must soak the fibers before use.Additional names for coconut fiber are coco-peat, coir-peat, coir dust, coir fiber pith, and coco coir.
Castings are the waste products of farmed earthworms. Castings contain enzymes and minerals, providing crops with easily absorbed nutrients. Like peat moss, they enhance water retention, aerate the soil, and inhibit fungus.
As worm castings decompose, they serve as a slow-release fertilizer. But, unlike chemical fertilizers, there’s no risk of burning your plants with worm castings. Since they’re pH neutral, they don’t affect soil pH.
Growth hormones in castings promote larger fruits and vegetables. One particular enzyme destroys pests.
Earthworm castings complement both garden and potting soils. To expedite seed sprouting, use a mix of 1/3 castings with 2/3 sand.
Whereas loamy garden soils usually have lots of earthworms, container gardening lacks this advantage. You can compensate for this drawback by adding worm castings to your growing medium.
Manufactured in Pittsburgh, Pennsylvania, this product is made of recycled newspaper and other natural materials. PittMoss is certified organic and free of contaminants, insects, pesticides, and weed seeds.
PittMoss has many of the properties of peat but without its ecological impact. For example, PittMoss enhances soil aeration, water retention, and nutrient availability. Regarding texture, it’s fluffy, lightweight, and drains well.
Three formulations are available, all pH neutral. “PittMoss Performance” contains a controlled-release fertilizer, for addition to potting mixes. “PittMoss Prime” lacks fertilizer, as a soil amendment. PittMoss Plentiful is a proprietary potting mix that includes compost, chicken manure, and fish emulsion.
In planning your food garden, if your soil is alkaline, consider adding peat moss. If the pH is fine, but the ground is too powdery or compact, amend it with peat alternatives. Organic possibilities are compost, coconut fiber, PittMoss, and earthworm castings.
Prepare your dream garden by identifying its soil pH and type, either testing it yourself or with an extension agent. Then, add any needed soil conditioners and recheck the pH. These preliminary steps are vital for plant-friendly soil.
Simplify matters with container gardening and a soil-less medium. One option is using PittMoss exclusively. Or, create a mix of peat moss, coco coir, and earthworm castings.