On March 5th I attended a workshop
sponsored by the Carolina Botanical
Garden: Soil is All. I share some information below
that appears relevant to our garden.
Some of the practices discussed, such as soil testing and amending already being applied to our garden. The presenters stressed the importance of humus/organic matter in soil, which provides space for air and improves water retention. Compost is the ideal way to add organic matter to soil because good quality compost improves the chemical, physical, and biological characteristics of the soil. Other, more readily available, sources of organic mater, such as leaves and saw dust, improve primarily the physical characteristics of soil (see Building Soil with organic amendments.)
The complex components of soil ecosystems were explained briefly. Topsoil and soil that supports growth is alive with both visible (worms, larvae and insects) and invisible organisms. Micro-organisms, especially the fungi, mycorrhizae* are essential for healthy plant growth. The interaction between certain fungi, mycorrhizae, and plant roots benefits both (symbiosis) and helps the plants absorb nutrients and resist disease http://aggie-horticulture.tamu.edu/faculty/davies/research/mycorrhizae.html.
Planting cover crops, especially legumes, helps maintain healthy mycorrhizal populations . Tilling and leaving soil bare disrupts this beneficial soil ecosystem.
In addition to cover crops, and intensive planting, the workshop demonstrated and recommended use of mulch to cover bare soil. Placing mulch over the soil protects against soil erosion, suppresses weeds, stabilizes soil temperature, reduces water loss from evaporation, and creates a barrier between plants and soil-borne diseases.
Some of the practices discussed, such as soil testing and amending already being applied to our garden. The presenters stressed the importance of humus/organic matter in soil, which provides space for air and improves water retention. Compost is the ideal way to add organic matter to soil because good quality compost improves the chemical, physical, and biological characteristics of the soil. Other, more readily available, sources of organic mater, such as leaves and saw dust, improve primarily the physical characteristics of soil (see Building Soil with organic amendments.)
The complex components of soil ecosystems were explained briefly. Topsoil and soil that supports growth is alive with both visible (worms, larvae and insects) and invisible organisms. Micro-organisms, especially the fungi, mycorrhizae* are essential for healthy plant growth. The interaction between certain fungi, mycorrhizae, and plant roots benefits both (symbiosis) and helps the plants absorb nutrients and resist disease http://aggie-horticulture.tamu.edu/faculty/davies/research/mycorrhizae.html.
Planting cover crops, especially legumes, helps maintain healthy mycorrhizal populations . Tilling and leaving soil bare disrupts this beneficial soil ecosystem.
In addition to cover crops, and intensive planting, the workshop demonstrated and recommended use of mulch to cover bare soil. Placing mulch over the soil protects against soil erosion, suppresses weeds, stabilizes soil temperature, reduces water loss from evaporation, and creates a barrier between plants and soil-borne diseases.
All mulches block sunlight, so prevent
seeds already present in the soil below from sprouting. Compost can be used as
a mulch, but allows wind-borne weeds to grow vigorously. In contrast, other
mulches, such as landscape cloth, newspaper, or a thick layer of leaves, grass
clippings, straw or wood chips, usually don’t provide the conditions that wind-borne
seeds need to sprout.
At the UNC Campus Community Garden a thick cover of leaves is used for mulch. Sometimes mulch is placed around small plants. Alternatively, existing mulch can be cut or moved aside to place transplants or seeds.
Many mulch materials decompose, adding organic mater to the soil, and must be replaced yearly. The book that is our primary gardening guide, Weedless Gardening, by Lee Reich, provides a mulch guide (page 24-25) and recommends adding mulch whenever bare soil is visible (page 48). Currently, some of our beds are mulched with decomposing cover crops, but bare soil abounds. In the future, we should consider how best to apply mulch to our garden.
-- Kris Weigle
At the UNC Campus Community Garden a thick cover of leaves is used for mulch. Sometimes mulch is placed around small plants. Alternatively, existing mulch can be cut or moved aside to place transplants or seeds.
Many mulch materials decompose, adding organic mater to the soil, and must be replaced yearly. The book that is our primary gardening guide, Weedless Gardening, by Lee Reich, provides a mulch guide (page 24-25) and recommends adding mulch whenever bare soil is visible (page 48). Currently, some of our beds are mulched with decomposing cover crops, but bare soil abounds. In the future, we should consider how best to apply mulch to our garden.
-- Kris Weigle
