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How to Germinate Seeds Using Vermiculite

Vermiculite is a mineral that is prized in gardening for its lightness and aeration properties when added to soil mixes. Often used in commercial potting mixes and seed-starting soils, vermiculite is also available on its own from garden stores and nurseries. It works especially well for seed starting, as the lightweight material makes it easy for a small seedling to push through. Start seeds directly in vermiculite or mix up a seed-starting mix of your own.

Vermiculite Only

Fill seed-starting pots with vermiculite. Choose a fine grade of vermiculite or sieve standard grade vermiculite through a fine mesh and use the smallest particles for seed starting.

Water the vermiculite until it is evenly moist. Plant seeds in the center of each pot to a depth twice that of the seeds' circumference.

Cover the pots with plastic wrap to conserve the moisture in the the vermiculite as the seeds germinate. Place pots in a warm room until germination occurs.

Remove plastic wrap once sprouts appear. Move the pots to a warm, sunny windowsill and keep the vermiculite moist.

Apply a half-strength balanced liquid fertilizer to each seedling pot. Fertilize once a week until the plants are ready to be transplanted into new pots or outdoors.

Vermiculite Mix

Mix 1 part vermiculite with 1 part peat moss and 1 part sterilized compost. Fill seed starting pots with the mixture.

Moisten the potting soil then sow seeds to a depth twice their circumference. Cover each seed with vermiculite only instead of the potting mix, as vermiculite is lighter and easier for the seedling to break through.

Cover the pot with plastic wrap and place in a warm room to germinate. Remove the plastic wrap once germination occurs and move to a warm, sunny windowsill.

Fertilize with a half-strength liquid fertilizer two weeks after seedlings have emerged. Compost has enough nutrients to carry the seedlings through the first two weeks of life.

Tip

Vermiculite doesn't form a crust as the surface dries, so is well suited to seeds that require shallow planting.

Warning

Vermiculite has no nutrients in it, so fertilization is required immediately with vermiculite-only planting or the seedlings will die off.

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