Can You Grow Nopal Cactus From Seed?

Seed Extraction and Preparation

• Nopal cactus seeds germinate unreliably even under the best of conditions, but there are a few things that improve the odds of successful sprouting. Extract the seeds in late summer as soon as the fruit ripens. The fleshy pulp must be removed because it inhibits germination. Spread the clean seeds on a baking sheet and allow them to air-dry in the shade for one week. The seeds need to ripen for at least six months before sowing to improve their germination, so store them in a paper bag in a cool, dry place until the following spring.

Sowing

• Correct sowing practices will significantly improve the odds of germination, even in recalcitrant seeds such as those of the nopal cactus. Fill individual pots or a large nursery flat with a moistened 50-50 mix of milled peat and perlite or coarse sand. The top 1/4 inch of the container should be left empty. Scatter the seeds evenly across the peat mixture, then gently press the seeds onto the surface to anchor them. The seeds sprout best when exposed to the light, so they mustn't be covered by soil. Instead, spread a single layer of coarse perlite over the seeds.

Germination Process

• Light exposure, constant heat and high humidity are all vital to the successful germination of nopal cactus seeds. Position the pots indoors near a south-facing window or outdoors inside a lightly shaded cold frame, then cover them with plastic wrap. A daytime temperature range of 85 to 90 degrees Fahrenheit should be maintained with a heating coil or germination mat, with nighttime temperatures of 65 to 70 F. Nopal cactus seeds are small and easily dislodged, so water the seeds from the bottom by placing the pots in a shallow tray filled with 1 inch of water until the water is absorbed into the soil. Healthy, viable nopal cactus seeds will germinate in roughly two to three months, with less vigorous seeds sprouting at random thereafter.

Transplant and Care

• Transplant the nopal cactus seedlings into individual 3-inch pots filled with cactus formula potting mix once they reach 1/2 inch in diameter. Bright light is especially important to cactus seedlings, so place them in a sheltered area with an abundance of sunlight and light, dappled shade at midday. Gradually acclimate the seedlings to direct sun. Fungal and bacterial infections are still a threat, so water only when the top 1/2 inch of soil dries out. Although the seedlings may survive in the ground by the end of their first year, it is best to grow them in pots until they produce an abundance of roots so they can better handle the unpredictable conditions found in many gardens.