Building Healthy Soil

(1/30) Maybe you found yourself in the same predicament I landed in when I moved to Adams County. It often happens when someone moves to a new development or a piece of property that once was part of a tired farm. You’ve got land, a clean canvas on which to landscape and build gardens, but the soil is nutrient poor and nearly devoid of life. So, what happens now? We start at the bottom; we build healthy soil!

It helps to think of a garden as an ecosystem, but we also have to realize the garden we build in Pennsylvania really wants to be a forest. That doesn’t mean we need to plant trees; it means our work needs to mimic the processes that would occur in a forest. When you walk in a forest you see very little bare ground; it is covered in debris — leaf litter, dead twigs, stems of herbaceous plants, etc. Dig through the leaves and you begin to see white threads — fungi — among the damp leaf remains on top of the soil. The top soil layer is rich with humus; you might see a beetle or ant moving material as well. If you dig deeper into the soil, it’s a rich brown, and full of life. You can see some of it — the larger creatures like worms, centipedes, grubs, etc., — but you’ll need a microscope to view most of them.

All these creatures make up the soil food web. They maintain a forest’s fertility by digesting the forest’s debris and turning it into rich, organic humus. Organic material holds soil moisture, keeps mineral nutrients from washing away, and keeps the soil porous for water and air to reach the roots. Fungi obtain soil nutrients and share them with plants. There are bacteria that form relationships with plants, exchanging nitrogen from the air for sugars produced by photosynthesis. Other bacteria busily use different chemical forms of nitrogen for their own food, forming it into the nitrate plants can absorb.

Once the trees are removed, its up to us to maintain the soil. Luckily, there are ways we can work with nature to make this happen. Do you remember pictures of deep, dark prairie soils in your elementary school geography book? In the prairies, long rooted grasses and forbs are the dominant plant type. Above ground plant material and a portion of the roots die and rebuild every year, and the dead material supplies the soil food web. It’s not the same mix of organisms we see in Mid Atlantic forests, but the principle is the same.

Agriculture in the Mid Atlantic is turning more toward this prairie-like, no-till method of soil building in a process called Regenerative Agriculture. Instead of using herbicides, winter cover crops planted each fall are cut back mechanically the following spring. The seeds for the year’s crop are planted directly into the soil through the debris. It takes special equipment to handle this at the scale of acres, but we can use some of these methods on our smaller spaces. We can grow cover vegetation for the purpose of allowing it to reach the point just before it sets seed, and then mow or cut it. There are a few easy-to-handle species that are good for this ‘green manure’ method, each with different characteristics to be considered.

Legumes are a group of plants that form relationships with Rhizobium, soil bacteria that live within roots cells of members of this plant family. Rhizobium takes nitrogen from the air and turns it into a form the legume can use in exchange for the sugars the host plant can provide. Cowpeas and crimson clover are two legumes that can be planted for cover and to enhance soil nitrogen. Cowpeas die during our winters, but chrisom clover often makes it until spring. The blooms of crimson clover are attractive to both pollinators and gardeners.

Oats grow until they are killed by frost. Besides not having to cut it in the spring, you have a mulch covering into which you can set out started plants, but not seeds. If you sow a mixture of a legume and oats you’ll be adding nitrogen, too.

If you have a vegetable garden laid out in permanent beds, you can plant these cover crops in the beds in the fall after the vegetables are removed. In the summer, anytime a crop is finished, you can immediately cover the space with buckwheat, a plant that germinates quickly, matures in about four weeks and prevents weeds from starting. This plant also attracts pollinators, but if left to produce seeds, which happens shortly after flowers appear, they sprout and get weedy.

Mulch around plants and between rows to retain moisture and shade the ground from the hot summer sun! For extra weed blocking benefit, save your newspapers to spread beneath the mulch.

If you use animal manure, a powerful organic fertilizer, allow it to sit and compost before using it.

Finally, I cannot extol the benefits of compost enough! Any vegetative material – kitchen scraps, coffee grounds, yard wastes, etc. – but not oils or animal products! – is compostable and there are several different methods to handle it, depending on the size of your garden, the amount of waste you accumulate and the aesthetics of your landscaping. (Information about composting is available at https://extension.psu.edu/home-composting-a-guide-for-home-gardeners.) Composted material can be added immediately to your garden beds where it releases valuable nutrients that feed your soil, which in turns, feeds your plants.

Remember that if we garden like a forest, we will retain moisture, we won’t leave bare patches, and we will provide the soil organisms with a full buffet. They will return the favor with healthier plants and tastier vegetables.