Green Bean Plants in Vermiculite

Vermiculite Benefits

• Vermiculite comes from mica, a glasslike mineral. When heated to high temperatures, the mineral expands. The expansion allows it to absorb more water. The water absorption helps keep the planting medium moist while allowing any excess water to drain out. Vermiculite also provides aeration to the growing medium and prevents it from compacting. Compacted growing mediums absorb water and nutrients poorly, and bean roots have difficulty accessing oxygen in the soil. Vermiculite doesn't provide a suitable growing medium on its own due to its fine texture and lack of nutrients.

Amendments

• Adding amendments to the vermiculite makes it suitable for green bean growing. Peat moss or compost provides body to the vermiculite so the bean roots can better establish themselves. Compost also provides trace nutrients. If you plant in equal parts compost and vermiculite, the beans require no fertilization since bean roots create their own nitrogen and only need the trace nutrients found in the compost. A slow-release fertilizer is necessary if you use peat and vermiculite, since neither material contains trace nutrients. You can also use vermiculite with potting or garden soil, if desired.

Seed Starting

• Bean seeds are typically sown directly in the garden bed or their permanent container, since they germinate quickly and tolerate transplanting poorly. The seeds sprout in seven days or less. Garden soil may develop a hard crust as the surface dries, even though the soil is moist just beneath the surface. Bean sprouts may have difficulty penetrating the crust, so sprouts emerge later than expected. Fungus on the soil surface may also infect tender sprouts and cause them to die. Cover the seeds with vermiculite instead of garden soil after sowing them in the bed. The vermiculite doesn't crust over and it retains the necessary moisture for germination. It's also sterile, which prevents fungal problems on young bean seedlings.

Container Gardening

• Most varieties of beans grow well as a container plant. They take up little space and have minimal nutrient needs, which makes them well suited to containers. Soil in containers compacts easily and dries out quickly. Using a potting mix containing vermiculite prevents compaction and helps the soil retain moisture longer. Use equal parts vermiculite, peat moss and compost for a homemade potting mix in the container. Substitute ground wood bark for the peat moss or compost, if desired. Vermiculite is also lightweight, which can make a heavy container of bean plants easier to move.