The Sweetest Beet: Basics of Soil Nutrition
To grow well, beets need neutral to slightly alkaline soil and proper thinning (since in most cases, each beet seed is actually a capsule containing 2-4 seeds).
But beets are also a little pickier in how they absorb and utilize soil minerals, and they have a hard time producing if the ones they need aren't available. To avoid common pitfalls and grow high quality, truly delicious beets, make sure they're getting these specific minerals.
Boron deficiency, the most common beet problem, is known as black heart and is caused by a shortage of available boron. Boron is less available to plants in strongly alkaline and very fertile soils, which may need to be amended.
- Symptoms include: Distorted young leaves, scorched-looking older leaves and black, corky spots on the roots.
- To treat: Foliar feed with liquid seaweed fertilizer for immediate results or add 1 teaspoon Borax per gallon of water per 100 square feet.
Magnesium strengthens cell walls, increases sweetness and yields, and improves uptake of other nutrients including nitrogen, phosphorus and sulfur. This can make magnesium-deficiency a little trickier to diagnose, since a shortage of magnesium may result in lack of available phosphorous, and appear to be a phosphorous deficiency.
- Symptoms include: Stunted growth, flavorless roots, and leaf yellowing in the tissue between veins, progressing to dark spots on the leaf margins.
- To treat: Water with 1 Tablespoon Epsom salts per gallon of water, or amend with dolomitic limestone or Sul-Po-Mag for a longer-term solution.
Potassium, one of the three macronutrients denoted by a "K" on most fertilizers, supports strong, vigorous growth, is essential to sugar production, and regulates transpiration, making the plants better able to tolerate heat, cold, shade and drought.
- Symptoms include: lesions along midribs, older leaves wither and collapse around the plant, young leaves curl and turn yellow or brown along the edges, undersized roots, "off" flavor
- To Treat: If a soil test indicates that the soil is acidic, foliar feed with fish emulsion or seaweed extract, mix one cup of wood ash per 100 square feet, or fertilize with cottonseed meal, greensand or poultry manure.
Calcium, while considered a micronutrient, is just as essential as N, P or K. It is a building block of plants' cell walls, and also regulates acidity and magnesium uptake. It's more common to find high levels of calcium than low ones, but in areas with acid soils calcium deficiency is common.
- Symptoms include: Youngest leaves yellow and curl downwards at the ends, forming a hook shape, while older leaves wither.
- To treat: Spread lime, bonemeal or wood ash on acid soils.
- Keep in mind that high levels of calcium are more common, and inhibit magnesium uptake.