Peat The Different Kinds and How to Use Them
Peat of various kinds is purchased each year in huge quantities by amateur gardeners and landscape men for incorporating with the soil to improve its quality.
Wherever new homes are built and lawns are to be made, wherever the planting of trees, shrubs and evergreens is to be undertaken, peat products may be employed. They may also be considered for use wherever new flower borders are to be prepared or old ones refurbished, vegetable gardens improved, rock gardens and wild gardens conditioned, or wherever seeds are to be sown in pots or flats or cold frames, and wherever mulching is to be practiced. Whether or not a peat product is actually used may depend upon comparative costs and other circumstances.
Leaf mold and other decayed vegetation play an important role in enriching the soil. Under natural, uncultivated conditions, they are returned to the earth by the plants that spring from it. Under garden conditions, however, they are mostly removed in the form of crops, or in the various tidying-up and hygienic processes that go with gardening. Peat is a good replacement for these valuable materials, and in its various forms (these will be discussed shortly) affords an easy and effective means of adding to the soil the bulky organic matter it needs.
Needs of Garden Soil
Most garden soils require periodic additions of organic matter (humus or humus-forming materials) to maintain them in reasonably fertile condition. Ordinary fertilizers do not supply organic matter in sufficient amounts to bring about significant improvement in the physical condition of the soil.
Fertilizers add plant nutrients (nitrogen, phosphorus, potassium and other elements necessary for plant growth) and because of this are valuable and needed aids to good gardening. By themselves, however, they are rarely enough.
To improve garden soils and to maintain them in a high state of fertility, it is important to add to them periodically both plant nutrients and bulk organic matter. Organic matter is particularly important in improving soil structure—in maintaining a desirable physical condition.
It is true that all bulk organic matter contains some nutrient elements, which, as the material decays, are gradually made available to the plants. Likewise, all fertilizers of organic origin (but not those of synthetic or mineral origin) add some humus to the soil.
But organic fertilizers, such as dried blood, tankage, and cottonseed meal, are used primarily for their nutrient content; the small amount of humus they add is of little importance. On the other hand, many bulky organic materials such as compost, leaf mold, commercial humus, peat moss and green cover crops are valued chiefly for the very considerable amounts of humus or humus-forming material they provide.
In a simpler horticultural age the gardener and farmer supplied their soils with both bulk organic material and liberal amounts of nutrients by the generous use of animal manure mixed with straw or other bedding material's. This was sometimes supplemented with bone meal or superphosphate, to make up for the phosphorus deficiency of most animal manures.
Most mid-twentieth-century gardeners cannot obtain manure in amounts sufficient to maintain the humus content of their spils at desired levels, and many, even if they could, would prefer to use other forms of bulk organic matter. There are several of these fairly commonly available; among the most popular and easily procurable are the various kinds of peat. Because peats (including peat moss) vary greatly, it is essential to know something about their characteristics to be able to purchase them advantageously. Unfortunately these materials are not well standardized.
What Peat Is
The term “peat” is correctly applied to vegetable matter (plant remains) that has accumulated and partially decayed under water or in locations waterlogged most of the time. The character of a particular peat depends upon the kinds of plants of which it is composed, the rate and state of their decomposition, and the chemical contents of the water in which the decay took place.
Peats are related to “mucks” so closely that it is not practicable to draw a fine line of distinction between the two. There are intermediate soils that one expert might term muck, another peat. In general, muck contains much more mineral material than peat, and the plant remains in it have decayed so far that they can no longer be recognized; they have become formless humus.
In true peats the structure of the stems, leaves, etc., of the plants of which the material has been formed can be clearly discerned, at least by an experienced person with a good magnifying glass. Peat is more spongy or more fluffy than muck and weighs much less. Mucks are rich soils and can be worked to give most excellent crops, but unless muck can be obtained locally at comparatively small expense it should not be considered as a substitute for peat; even if obtainable at advantageous prices, it cannot be employed in all capacities as a peat substitute, as will be shown later.
Kinds of Peat
Peat moss, moss peat or Sphagnum peat is
formed chiefly from the decay of Sphagnum mosses, although it frequently contains small quantities of the remains of other Sphagnum bog plants such as Ferns, Sundews and terrestrial Orchids. Characteristically it is strongly acid (pH 3.5 to 5.0) in its reaction. It is loose, spongy and normally varies from yellowish-brown to rich dark brown.
Its nitrogen content is low (about 1 per cent) and other nutrients it contains are negligible. Peat moss will absorb between six and fifteen times its own dry weight of water.
Sedge and Reed peat, often sold commercially as humus or peat humus, is formed chiefly by the partial decay of Sedges, Reeds, Cat-tails, certain Grasses and other shallow-water and swamp plants. It is ordinarily much less acid than peat moss, its pH value ranging between 4.4 and 6.5 When of good quality, it is light, powdery when dry, and usually dark brown to black. Its nitrogen content is decidedly higher than that of peat moss, being 2 to 3 1/2 Per cent. Other nutrients are negligible. Sedge and Reed peat will absorb between three and six times its own dry weight of water.
In addition to being sold in a raw state, Sedge and Reed peat is offered as cultivated peat. To produce cultivated peat, the bogs are drained and sown down with cover crops. The green cover crops are then disced under and allowed to decay. When this has occurred, the surface layer is scraped off, piled in heaps to drain and then is screened and packaged.
This cultivating process is akin to composting, and the product is claimed to encourage plant growth better than unprepared peats.
Other Peats. The two types of peat described above are those that most commonly enter commerce. Another peat is Hypnum peat, derived from the partial decay of Hypnum and mosses other than Sphagnum, together with Sedges and some other plants. It is light and spongy, brownish or drab and usually slightly acid, neutral or even alkaline. Hypnum peat is low in nitrogen and absorbs water to about the same extent as Sphagnum peat.
Forest peat or peat mold consists of the partially decayed roots, trunks, branches, bark, leaves, etc., of various trees and shrubs. It is brown and fluffy but less fibrous than peat moss and usually contains an abundance of small particles of wood. Its nitrogen content is 1 to 2 1/2 per cent and it absorbs between four and eight times its own dry weight of water.
Sources of Peat. Peat deposits occur in many parts of North America, and a considerable amount of domestic peat is marketed. This includes Sphagnum peat moss, which is found chiefly north of a line stretching from southcentral Maine through north-central New York to north-central Minnesota and British Columbia, and Sedge and Reed peat, which predominates south of that line. Some Hypnum peat is marketed from northern states. The domestic supplies that come to market are supplemented by peat moss imported from northern Europe, chiefly Germany and Holland.
Peat is marketed in bulk and in bales, cartons and bags. Bulk peat is often nearly saturated with water, but packaged and baled samples normally contain little moisture, and most frequently its percentage is not stated. Wet bulk peat is commonly sold by the cubic yard rather than weight. If of good quality, a cubic yard is likely to contain about 450 pounds of organic matter. Dried and shredded peat is much lighter, weighing usually about 8 pounds per bushel when loose. Bales of peat vary considerably in size and this the buyer must take into account when comparing prices. Their compressed volume may be from five to sometimes more than eight bushels (considerably more, of course, when the peat is opened and loosened up).
A typical bale of peat moss of a large size measures about 36 by 23 by 23 inches and weighs about 175 pounds. Such bales are sold as containing 22 bushels (measured before compression) or about one cubic yard of loosened, fluffed-up material. Smaller bales, weighing about 100 pounds and containing about 12 bushels, or slightly more than half a cubic yard of loosened material, are commonly sold.
Measurements and the contents of bales as expressed in bushels of peat moss vary considerably. As the United States Department of Agriculture points out in one of its circulars, “The consumer’s interest would be better served if the quantity of peat in a bale could be standardized, and the standardization put on the basis of weight rather than volume.”
And there lies the crux of the whole situation. The purchaser of peat for horticultural use is primarily interested in the actual weight of organic matter he gets for his money (he should not pay for water content).
In addition to learning the actual weight of organic matter it contains, the gardener is interested in knowing how acid peat is—in other words, its pH value.
Acidity and alkalinity are measured according to a scale in which pH. 7 represents a neutral condition, neither acid nor alkaline. As the figure following the pH symbol increases above 7, so does the degree of alkalinity it represents; as it decreases, it indicates' increasing acidity. A soil having a reaction of pH 6 is considered slightly acid, one rating pH 5 is considered acid, and one rating pH 4 very acid.
Some Points to Remember. In the United States, because of the Federal Trade Commission’s regulations, you are sure to get a fairly good product if you buy peat or peat moss under brand names or from reputable dealers.
Remember, however, that the value of these products, as measured by the actual weight of organic matter contained in a given quantity, may vary considerably within the Federal Trade Commission’s specifications. Under those regulations a content of 75 per cent peat is sufficient to warrant the use of the term “peat” to describe a product, and a content of 75 per cent peat derived from mosses makes it permissible to describe a product as peat moss or moss peat. Yet a really tiptop peat moss contains 95-99 per cent organic matter and a first-rate Sedge and Reed peat 85-95 per cent organic matter.
When comparing prices, remember that sizes of bales and other containers vary; and if you buy by weight, remember that moisture content of moist and wet peats varies.
Beware of irresponsible local “landscapers” and peddlers who sell black mucks as “humus” and “peat” to unsuspecting customers to spread on their lawns and for other garden purposes. Such sellers are most active in spring.
Muck, because it cakes over and partially seals the soil surface against the free entry of air, is not suitable for use as a lawn dressing or mulch.
Because it lacks sponginess and the waterholding and soil-loosening capacities of peat, muck is much less useful as a soil amendment. Its organic content is usually not more than 40-50 per cent.
If it can be procured cheaply enough, muck may be mixed with very sandy and gravelly soils with considerable advantage, but it cannot be regarded as a satisfactory substitute for peats having organic contents of 75 per cent or higher.
Because peats are used primarily as sources of organic matter, the economics of employing them should be balanced against the costs of other materials that provide this—for example, compost, leaf mold and decayed manure (here the fertilizer or plant nutrient values must be taken into consideration also).
Peat for Particular Uses
While the actual amount of organic matter you get for your money should be the first consideration when you buy peat, and its acidity a close runner-up for your interest and attention, other factors may rightly influence your judgment as to which particular peat product to favor.
On light, sandy or gravelly soils that are not
retentive oŁ water and that dry out excessively in summer, peat moss, because of its much greater water-holding capacity, is to be preferred to other peats, provided its price per unit of actual organic matter does not differ greatly from that of other types.
On very heavy, clayey soils that tend to hold water rather than permit it to drain away quickly, Sedge and Reed peat is usually to be preferred to peat moss if it can be obtained at approximately the same price for the same amount of actual organic matter.
For propagating purposes, peat moss, alone or mixed with sand, is the most useful product to make up beds in which cuttings are to be inserted to form roots. For mixing with soils in which seeds are to be started, either peat moss or Sedge and Reed peat is satisfactory. If the plants to be raised are kinds known to prefer acid soil, be sure an acid peat is used.
For mixing with soils in which pot plants are to be grown, peat moss is considered most satisfactory for acid-soil plants such as Azaleas and Camellias; Sedge and Reed peats are recommended for other types of plants.
For mulching (spreading as a surface layer on the ground over the roots), all types of peat are valuable but the more acid (low pH) types are the ones to use for acid-soil plants such as Rhododendrons, Azaleas, Mountain Laurel and Blueberries.
Peat for horticultural use should be finely shredded. Coarser grades are much used as litter in stables and chicken houses. Through this use, such materials are fortified by the addition of animal excrement and urine; used in gardens afterwards, they supply both plant nutrients and considerable organic matter.
Such peats are extremely valuable and are worth more (because of their fertilizer value) than plain peats. They may be available in local markets in bulk and are also dehydrated, ground, screened, packaged and sold over wider areas.