Bean plants are among the easiest vegetables to grow. They germinate quickly under the right conditions and produce flowers and fruit within 50 to 65 days, depending on the variety. If planted too early, though, beans may be slow to germinate or fail to germinate at all. Pay close attention to planting times and seed depth.
Under good conditions, beans germinate in eight to 10 days. Beans may take two weeks or longer if the soil temperature is under 16 degrees C (60F). Wait until daytime temperatures are above 24 degrees C (75F) before planting bean seeds for fast germination.
Many people soak bean seeds before planting, but this procedure can actually hamper germination by causing the seeds to crack or rot. Beans germinate best in evenly moist, but not soggy soil. Heavy clay soils tend to stay wet longer in the spring. Amend them with organic matter such as compost or manure to improve drainage, or plant green beans in raised beds.
In addition to improving drainage, raised beds warm up earlier in the spring, making them a good choice for gardeners. Another option is to lay black plastic over the soil two weeks before planting bean seeds. The plastic warms the soil and speeds up seed germination. Remove the plastic before planting or cut slits in the plastic and leave it in place all summer. Plant green bean seeds 2.5 cm (1 inch deep) in sandy soils and 1.25 cm (1/2 inch) deep in clay soils that stay cold longer.
Planting beans in cups is a common pre-school activity because the seeds germinate predictably, offering a first lesson in gardening. Beans don't handle transplanting well, though. Plant seeds directly in the garden after the soil has warmed for best results, rather than starting seeds indoors.