Peanuts have a long growing season and require 100 to 130 depending on the variety of frost-free days to reach maturity. USDA Zone 7 and above should plan on starting seeds for peanuts indoors 4-5 weeks before the last anticipated frost date. Zones 8 and above can start inside to get a head start, or sow directly into your garden beds after your last frost date.
Using your favorite seed starting mix, remove the nuts from their protective shells and plant your seeds about 1” below the soil line, and water well. Keep the soil moist but not wet while waiting for germination, and avoid letting the soil dry out while the plant babies are growing. Germination should happen between 5-12 days. Because peanuts produce extensive root systems quickly, it might be a good idea to use a peat pot or newspaper pot to sow into, so that you can transplant directly into your garden beds with minimal disturbance of the roots. If this is not possible, handle the plants as gently as possible when transplanting.
Peanuts require warm soil and as much sun as you can get them. Prep a good spot in your garden with rich compost and at least 10” of well-draining, worked-loose soil. If your clay is too heavy with clay, you might consider a raised bed, or growing your crop in grow bags to ensure good drainage and loose soil for the fruits to develop. Space your seeds or transplants a good 10-12” apart and water well. Because peanuts need loose soil, you may need to come in with your garden fork and jiggle the soil around the plants a bit as they grow. I do this for the first time when the plants have reached about 6” in height, and once more when they are about 8”. The plant will develop runners as it grows, and each of these runners will develop blossoms. The flowers will wilt and bend down, but you should not pick them off. These downward stems are called "pegs." Your peanuts will grow off of these pegs, and the stems need to find their way underground in order to grow those peanuts. By keeping the soil loose, you make it easier for the pegs to get underground.
After the pegs have found their way underground and the plants themselves are about 12” tall, you should gently form the soil into small hills around each buried peg and around the base of the plant. Doing this provides extra warmth and protection for the peanuts growing on the ends of the buried pegs. Spread out 2” of a light mulch like straw or grass clippings over the area immediately after creating the hills. Do not use heavy mulches like wood chips here. Additional pegs may need to break through the soil, and they will not be able to do so with heavy mulches in the way. Water if needed throughout the growing season to achieve the desired 1” per week of water that most veggie crops need.
Fertilizers are not usually necessary to begin with when growing peanuts, but if you do opt to use a fertilizer, make sure that it does not contain large amounts of nitrogen. Peanuts supply their own nitrogen. Adding more nitrogen to this will produce very bushy plants with thick foliage and little fruit yield. We’ve found that a light application of gypsum just after flowers start to fade will help contribute to large and healthy nut formation.
The biggest threat to your peanut plants are squirrels, chipmunks, and other small critters looking for a free feast. Placing mesh fencing around your plants could help save your crop if these guys are a problem in your garden.
Peanuts are usually bothered by insect pests, though occasionally you may see pressure from cutworms, cucumber beetles, and aphids. Use a trusted organic spray if needed to save your crop as peanuts, being an underground crop, are susceptible to chemical uptake.
You should plan on harvesting the peanuts before the first frost of fall occurs, since peanuts at this stage are still sensitive to frost attacks. The plant will turn yellow and begin to wilt when it is ready to be harvested. Gently dig up the entire plant with your gardening fork, lifting it up from beneath the roots. Shake off most of the soil clinging to the roots. A healthy plant will usually yield about 30 to 50 peanuts.
After harvesting, you’ll need to dry the plant out. The easiest way to do this is to hang the plant indoors in a dry location for about a month. For the first one to two weeks, let the peanuts cure on the plant as they are in a warm, dry spot. For the remaining two weeks or so, pull the nuts off and let them dry in the same warm, dry spot.
To store peanuts, leave them in their shells and place them in an airtight container in the refrigerator up to 6 months.
Peanut, Arachis hypogaea
Pollination, self; Life Cycle, perennial grown as annual; Isolation Distance, 50 feet
Peanuts require a long and warm growing season to produce. Flowers are self-pollinating, but very attractive to bees and produce a fertilized ovary (which becomes the fruit we know as peanuts) that grows downward into the soil a few inches. Mark the plants you want to use for saved seed during the growing season, as this will be the best time to identify the strongest plants. The plant is pulled from the soil when the leaves have turned yellow. Hang plants in a cool, dry place with good air flow for drying for at least 3 to 4 weeks. Strip the odes from the vines and store in a burlap sack.