Fertilizing beets works best with a low nitrogen mix that sends energy into roots. Look for fertilizers with numbers like 5-10-10 where the middle and last values beat the first. These mixes give you phosphorus and potassium that roots need without pushing leaf growth.
Picking the right beet fertilizer made a huge difference in my own garden. My first beet crops had beautiful tall green tops but tiny roots the size of golf balls. I had been using lawn fertilizer with too much nitrogen. The plants put all their energy into leaves instead of the roots I wanted to eat.
SDSU research shows why nitrogen for beets needs to stay in check. Too much nitrogen grows lush tops at the cost of root size. The plant thinks it should make more leaves to catch sun instead of storing sugar in the root. Stick to 1.7 pounds of nitrogen per 1000 square feet as Alaska Extension suggests for the right balance.
Boron is one nutrient that beets need more than most garden crops. Maryland Extension notes that boron shortages cause black heart disease inside the roots. Add 6-7 tablespoons of borax per 1000 square feet if your soil tests low for boron. But don't add more since excess boron poisons plants just as fast as a shortage hurts them.
Compost makes great slow release food for feeding beet plants. Work 2-3 inches of compost into the soil before planting. This gives your crop a steady supply of nutrients all season long. Compost breaks down at a pace that roots can use without getting too much at once.
Side dress your beet plants with extra fertilizer once they reach 4-6 inches tall if the leaves look pale or growth slows down. Sprinkle a light amount of balanced fertilizer along the rows about 3 inches from the stems. Water it in well so the nutrients soak down to the root zone where plants can grab them fast.
Watch for signs that you gave your beets too much food. Leaves that grow dark green and floppy point to excess nitrogen in most cases. Roots that stay small while tops grow huge tell the same story. Cut back on feeding if you see these warning signs and let the plants put energy into roots for a while.
Test your soil before each season to know what your garden needs. Many yards already have plenty of nitrogen from lawn care or old compost piles. A test tells you if you need fertilizer at all or just some boron and potassium. Start with less and add more only if plants show signs they need it.
Read the full article: How to Grow Beets from Seed Perfectly
