Is your soil fertile? A balance of nutrients is essential for plants to thrive. Too much of one can be just as bad as too little.
Plants need Nitrogen (N), Potassium (K), and Potassium (K), expressed as NPK, in the largest quantities. They need other trace elements as well.
What is fertile soil? Fertile soil is dark and crumbly and has a fresh, earthy smell. It holds water well. Get to know your soil by observing the color, smell, and feel of it.
The first step to healthy soil is in performing a soil test. All of Southside Community Land Trust’s gardens test their soil before any food is grown.
Many times, city soils will show high levels of contaminants. If this is the case, it’s best to build a raised bed and purchase healthy soil.
Sandy - sandy soil is gritty and does not hold together when wetted and squeezed. It has good drainage, but is low in nutrients and doesn't hold water well.
Clay - clay soil and silt stick together when wetted. When dry, they are rock hard. They contain important nutrients, but are difficult for roots to break through.
Loam - loam is a combination of sand, silt, and clay. When wetted, it is crumbly. It holds water and nutrients well and is easy for roots to penetrate.
Nitrogen - gives plants lush, green, leafy growth
too little: small, pale or yellow leaves
too much: rapid growth, nitrogen burn, disease, sucking pests, delayed flowering
sources: alfalfa meal, blood meal, compost, cover crops, fish meal/fish solids, barnyard manures
Phosphorus - helps stimulate flower, fruit, and root growth
too little: purplish leaves or stems, poor flowering
too much: aborted flowers
sources: bone meal, cover crops, poultry or rabbit manures, soft rock phosphate
Potassium - helps with growth and disease resistance
too little: crispy brown leaf edges, curled lower leaves
too much: delayed flowering, poor roots
sources: compost, granite meal, kelp meal, wood ashes
Calcium - needed for cell reproduction and protein synthesis
too little: curled leaves, weak stems
too much: delayed flowering
sources: lime, gympsum
Trace minerals: iron, manganese, zinc, copper, boron, and molybdenum are needed by plants in trace amounts. Too much will harm plants.