Saffron is hardy to zone 4, and has potential in some zone 3 areas.
Each year more saffron corms will multiple from the original corm, producing more flowers each year. After 4-5 years of harvesting, the corms should be relocated, or soils should be amended to replenish fertility. Your saffron corms are rated at 10+/centimeter grade, which is considered flower production size.
Saffron can tolerate a variety of soil pH (6-8), and prefer a dry, well-drained, full sun location. Saffron seems to enjoy fertilizer so don’t forget to add some compost to your planting to help improve daughter corm and flower development.
Plant your saffron corms as soon as you receive them in late summer/early fall. Plant 4-6 inches deep, and 4-6 inches apart. Mulch and plant corms deep enough into the soil to prevent frost exposure. Thoroughly water in your corms, and wait until you see growth above ground before you start watering them regularly. They should be watered during extreme drought or prolonged dry periods. They will flower first, during late October/early November, and remain vegetative through the entire winter. They will keep their foliage until July, when they will dry back and remain dormant until the fall. During dormancy they should not be watered. Natural rain or snow events shouldn’t be a problem.
Saffron stigmas should be collected once the flower reaches full maturity, then dried and cured for the best culinary appeal and health benefits. Drying should take place for several days in a cool, wind-free area, and jarred, and cured over the course of a few weeks.
Because this plant grows when no other plants are growing, it is a very welcoming food source for moles and voles during March and April especially. Please be cautious of rabbits and rodents when siting your plants. If planting in raised beds, install hardware cloth to help ensure your saffron remains yours and not your garden pests’.