7 Ways to Revitalize And Replenish The Raised Garden Beds
It is a wonderful thing that a raised garden bed is filled with healthy soil for the first time. The soil mixture is fluffy and porous, which is absolutely pleasant to use. It is ready to live with some new green friends.
But after one or two productive growing seasons, you will notice that the soil is a few inches lower in the frame, and the farming feeling is not as amazing as at first.
This is the problem of raising garden beds - loss of soil volume and fertility is inevitable.
One of the advantages of growing on a raised garden bed is to completely control the content and quality of the soil - but this may also be one of its biggest disadvantages.
In ground gardens, soil depletion is not a problem, because topsoil is the cornerstone of all organic improvers you throw at it. However, in elevated frames, the once loosely ventilated soil will settle and contract. The organic matter in the soil mixture will continue to decompose into smaller and smaller particles.
Since the soil microbiome in the raised garden bed is independent and contained, you need to closely monitor the soil health and make amendments every year to maintain the soil depth.
Autumn or early winter is the best time to repair the soil of the raised garden bed. However, before you begin to recklessly discard materials, it is important to immediately look at the soil in the raised garden bed to determine what it actually needs.
How to evaluate your soil
The totally unscientific way to evaluate the soil is to use your eyes, hands and nose to judge the cultivation:
Look at the color. If it is dark, it contains a lot of organic matter. If it is light, its organic content is very low even in wet conditions.
Feel the texture: Grab a handful of soil and rub it with your fingers. Good farming is a balance of minerals and organic particles - it should feel a bit gritty and slightly sticky.
Smell: Organic matter has a strong earthy smell. Soil with low organic content has poor air circulation and may smell sour.
Watering: Fully soak the raised garden bed and observe how it drains. If the water is absorbed into the soil within a few minutes, the organic matter is very high. If puddles and stands, organic matter is very low.
Of course, a proper soil test will tell you exactly what you need to raise the garden bed soil.
Only a detailed analysis of the dirt can provide you with accurate values of N-P-K nutrients, micronutrients, pH and organic content. These tests are cheap and can save a lot of unnecessary fertilizers and modifiers. Please contact your county extension office to learn how to obtain a soil test kit.
Seven Methods of Supplementing the Soil of the Raised Garden Bed
- Native soil
If the soil in the raised garden bed shrinks a few inches per year, it may lack a very important component: mineral soil.
Topsoil, garden soil and potted soil sold in bags usually contain very little actual soil, if any. Filling raised garden beds with 100% soilless media can bring some success, but over time, organic particles will collapse as they continue to decompose.
Since there is no soil structure to speak of, the contents of the raised garden bed may become pasty and greasy dregs. It will not drain well, retain moisture or diffuse air.
It may become expensive to replenish it with fresh organic matter every year, and it will not solve the fundamental problem of volume reduction.
This is where mineral soils can be used. Mineral soil covers most of the earth's land surface and is composed of sand, silt and clay in different proportions.
Mineral soil provides some much-needed physical structures. It is inorganic (because it will not decompose). It provides a permanent backbone for the raised garden bed, allowing organic matter to adhere when decomposing.
The best source of mineral soil is native soil from the backyard - as long as it is not contaminated with chemicals or heavy metals. Alternatively, clean mineral soils can be purchased in bulk or in bags, as long as you ensure that the products you purchase are mainly composed of clay and sand.
To improve the soil structure, fill the raised garden bed with at least 50% mineral soil. Add more than you think you need, because it will stabilize with rain and time. Leave enough space in the growth box, at least 2 to 4 inches for organic improvers.
As the soil settles to its final resting place, you can add more soil in the next year to restore it to the desired level. The advantage of mineral soil is that it stays in place and you don't have to reapply it year after year.
- Self made compost
If your soil drops only a few inches a year, and your raised garden bed soil has good bones, you can turn your attention to organic improvers.
The most popular of all organic improvers is homemade compost.
As an all-in-one soil conditioner, compost is a slow release fertilizer that can add a wide range of macronutrients and micronutrients required for healthy plant growth. It encourages microbial activity in the soil, creates better soil structure, and improves drainage and water holding capacity.
You can apply a 1-inch layer on the raised garden bed in autumn as a general maintenance to replenish nutrients and improve the soil level.
Add up to 4 inches of compost to the severely depleted bed.
- Rotten livestock manure
Animal excrement is an important part of the earth's soil food web and has been used as natural fertilizer for centuries.
The feces of chickens, rabbits, cattle, horses, sheep, goats and other herbivores are an excellent source of nitrogen, phosphorus and potassium.
Like compost, livestock manure will contribute a lot of organic matter to mineral soil and feed soil microorganisms that form good soil structure.
Rabbit faeces are the easiest to handle. Rich in nutrition, it is a kind of cold dung, mild enough to be used in the garden immediately.
Another good choice is chicken manure, whose N-P-K content is usually twice that of other livestock. This is a kind of hot manure, which must be composted before it can spread safely.
Feces of hot animals have very high nitrogen content, can burn plant roots, and may contain pathogens and seeds. To prepare a pile of fresh animal waste, add carbon rich materials, such as wood chips, dry leaves, and straw.
Keep wet and turn over daily to heat. Once the high heat of 113 ° F to 140 ° F is maintained for several weeks, it will decompose and have a consistency similar to that of soil.
In autumn, sprinkle 1 to 4 inches of compost manure on raised garden beds. It will be solidified locally and planted in spring
Biochar is very suitable for increasing the volume and fertility of your exhausted raised garden bed.
It is made by heating wood and other plant materials to 400 ° C to 700 ° C without oxygen. The resulting blocky charcoal has an incredibly porous surface area that can absorb and release nutrients into the surrounding soil.
Biochar was originally developed by farmers in the Amazon basin as early as 450 BC. It is then called terra preta (literally "black soil"), and the treated fields still exist today. Somehow, thousands of years later, the soil is still fertile and regenerates at a rate of 0.4 inches per year.
How biochar maintains fertility is a mystery. One theory is that because it absorbs nutrients like a sponge, leaching and runoff are greatly reduced. The other is that terragreta has a higher level of mycorrhizal fungi, which promotes the improvement of nutrient exchange in soil.
- Leaf mold
The leaf mold is very simple - just pile up your fallen leaves, moisten the pile, and wait. It will become dark and fragile humus within 1 to 3 years.
A little patience will eventually pay off. The resulting leaf compost is a good renewable material for covering, conditioning and improving the soil.
The decomposed leaf mold has high carbon content and low nitrogen content, containing a large amount of calcium, iron, chlorine, copper and other secondary nutrients required for plant growth. Since it is not fertilizer itself, it is better to add it to the raised garden bed after you have added the high nutrition correction.
In addition to contributing a little fertility to the mixture, the leaf mold also solves several soil problems that may occur in raised garden beds. It will help to drain, increase water holding capacity and neutralize the pH of poor soil. As a rich source of organic matter, it will keep the fat and happiness of soil microorganisms.
Lay a 3-inch layer of leaf mold on the raised garden bed as a nutrient cover. It depresses the soil and protects it from snow and wind. Like a warm blanket, it also helps to regulate the soil temperature and protect the many macro and micro organisms living below.
- Green manure
Several things were done in the winter garden with green manure.
Sowing in autumn, the plant grows until it is killed by frost. After the first thaw in spring, they were cut down and scattered on the soil.
Planting a mixture of hardy and nitrogen fixing plants will hold the soil in place and improve fertility. Like living mulch, mulch crops can also inhibit weeds, regulate soil temperature, balance water levels, and provide habitat for soil microorganisms.
Soil microorganisms like to live very close to living roots. Giving them a place to live through the winter will increase their number and diversity. The more microorganisms in the soil, the better the nutrient, energy and water cycle of crops next year.
Legumes such as dark red clover and winter peas will supplement nitrogen to the soil. Oats, annual rye and winter wheat will establish good soil structure to prevent erosion and keep weeds out.
These grains are also nitrogen scavengers that can absorb and retain nutrients, so they remain in the raised garden beds without being leached. Nitrogen is stored in plant tissues and released when plants are cut down and laid on the soil in spring.
- Garden covering
Once your raised garden bed is filled and modified, the soil should not be exposed in winter.
Applying a large amount of mulch topdressing is an important part of any soil management strategy. This is the last step in preparing a raised garden bed for the coming growing season.
Garden coverings can take many forms. Straw and sawdust are classic choices, but you can also use straw, crushed leaves, pine cones and many other organic wastes. Even a few layers of cardboard can be completed at a critical moment.
The mulch will maintain the quality of the soil you have just tried to create. Think of it as a protective shield, which can prevent the germination of weed seeds, prevent soil compaction and erosion, and keep the soil warm in winter.
Winter mulch can be placed on raised garden beds up to 3 inches deep to protect vulnerable soil microbiomes and their residents.