The term organic can have many meanings, but we can define it as plant remains for our purpose.
Such remains commonly decompose rather quickly, contain considerable amounts of the elements necessary for plant growth, and, if incorporated into the soil after serving their purpose as a mulch, improve the soil structure and add fertility.
Benefits Of Organic Mulching
Organic mulch may have several benefits in the garden. However, its value will vary considerably according to the conditions the individual gardener encounters.
In many cases, its greatest benefit lies in its effect on soil moisture.
By keeping the soil loose and porous, the mulch often increases the ability of the soil to absorb moisture.
Providing a protective covering reduces moisture loss from the soil surface.
It also may reduce the water run-off from the soil surface, thus conserving moisture and aiding in the prevention of erosion by both water and wind.
Better Medium For The Growing Plants
The soil under the mulch, particularly heavy soil, often is better aerated and serves as a better medium for the growth of plants and beneficial soil bacteria.
As a result, decomposition of organic material in the soil takes place more rapidly with a consequent release to garden plants of the fertility elements bound up in the organic matter.
Prevents Baking And Crusting The Soil Surface
It also prevents baking and crusting of the soil surface and usually aids weed control.
Under the mulch, the soil temperature tends to fluctuate less. Thus the soil is cooler in summer and warmer in winter.
This is taken advantage of in mulching perennials, where a mulch may cut down or prevent winter injury by keeping the soil temperature higher in winter and reducing the amount of soil heaving with its consequent root injury.
Value Of Organic Matter
Organic mulches also keep such garden products as strawberries, tomatoes, melons, and the like clean by preventing dirty water from splashing on them when it rains.
Aside from the value of organic matter as a mulch, it may have other benefits if it is worked into the soil as it decomposes.
With the addition of organic matter, the physical condition of the soil is improved.
Drainage becomes better on heavy soils. The water holding capacity of light soils is increased.
Heavy soils become better textured and better aerated. As it decomposes, it adds fertility to the soil. These, then, are some of the advantages of organic mulch.
Disadvantages Of Organic Mulch (Under Some Circumstances)
On the other hand, some disadvantages may be involved in its use under some circumstances.
For example, it must be maintained when organic mulch is used continuously on such plants as trees, shrubs, perennials, and other garden plants.
The mulch tends to cause the plant to produce many roots close to the soil surface.
If the mulch is removed, these roots may dry up as the soil surface dries, and the plant may be injured.
Winter Mulching Of Perennials
In some cases, particularly in the winter mulching of perennials on heavy soils, smothering of plants may occur due to excessive amounts of moisture about the roots.
Plants, like humans, do not like wet feet, and waterlogged soil sometimes may cause the plant’s death.
The organic mulch may sometimes reduce the soil intake of water by absorbing most of the rainfall and releasing the moisture into the air again by evaporation without any or very little of it reaching the soil.
Dry Peat Mulch
This usually is not too important, but a dry peat mulch has been shown to do that very thing.
Care should be taken to see that the mulch is free of mature weeds since an unclean mulch may add weed seed to the soil and increase the weed problem.
There is also some danger that the mulch may be a fire hazard if it becomes dry. It also may provide a haven for rodents.
Furthermore, it may be rather unsightly, although not necessarily so if good care is taken of it.
If the mulch is worked into the soil, care should be taken not to work in too much at one time, or temporary nitrogen starvation of the garden plants may occur.
The bacteria that decompose the organic matter in the soil use soil nitrates to do their job.
Shortage of Nitrogen For The Plants
This temporarily results in a shortage of available nitrogen for the plants. However, after the decomposition is completed, the nitrates become available for plant use again.
Therefore, the mulch should be worked into the soil in small amounts or additional readily available nitrogen in the form of sulfate of ammonia or ammonium nitrate.
They should be added at the rate of 1.5 to 2 pounds per 1,000 square feet of garden area when the mulch is incorporated.
In general, it would seem that the advantages of organic mulch in home gardening outweigh the disadvantages in most cases.
However, whether it will be of benefit depends to a large extent on the needs of the individual garden and the proper use of it by the gardener.
Paper Mulch Used On Pineapples Around 1915
Interest in mulch paper was aroused by results obtained from its use on pineapples and sugar cane in Hawaii, where it was used to control weeds about 1915.
Because of the results obtained there, many investigations have been conducted to determine its value with other crops.
Base Paper For Best Results
An impervious, black, asphalt base paper generally gives the best results. This is laid over the plant rows and the plants planted through it.
It may also be laid between the plant rows and the seeds or planted between the strips of paper.
The results obtained in these investigations have been somewhat variable, but certain conclusions about the value of mulch paper may be of interest to the home gardener.
While there does seem to be some beneficial effect exerted by the paper on vegetable crops, at least the increases obtained in most cases do not appear to pay for the additional costs incurred.
Most Beneficial With Warm-Season Crops
The use of paper seems to be most beneficial with warm-season crops.
However, it also appears to hasten the maturity of specific crops and may be profitable with crops with a high market value early in the season.
It also appears to be most beneficial under conditions unfavorable to the crop’s optimum development, such as poor soil, deficient precipitation, and low temperature.
Growing Season
Since there is no precise way in which the climatic conditions can be predicted in a given locality, the value of the paper from this standpoint can only be determined after the growing season is past.
Under favorable growing conditions, minimal benefit and sometimes detrimental effects are often produced.
The impact of the paper varies not only with local climatic conditions but also with each crop grown.
Value Of Paper For Crops And Weather Conditions
Therefore, each gardener must determine the value of the paper for their particular crops and conditions.
Warm season crops of high acre value and yield that are grown intensively are most likely to give the best results.
Weeds are eliminated to a large extent in the covered area, conserving the moisture and fertility they would use.
It also cuts down the cost of cultivation, but this usually is offset to a large extent by the added cost of laying and caring for the paper and the additional labor involved in planting and transplanting when it is used.
Organic Mulches Using Paper
As with organic mulches, the paper conserves moisture, keeps the fruits of low-growing fruiting crops clean, and keeps the soil in a loose, friable condition. However, in contrast to them, it tends to increase the soil temperature.
Although the paper has been tried out on a reasonably large scale by commercial growers in the past, very little of it is used at present except in a few unusual situations.
Special Value Of Paper
However, the paper may have a special value to the home garden enthusiast who is not particularly interested in the economic aspects.
Slight increases in earliness and quality, and a reduction in the labor necessary for cultivation, usually done by hand under such conditions, often appeal to the home gardener.
The weed control aspect also may have a special value to him, for the paper will retard the weeds for a few days or weeks when he may be on vacation or busy with other work.