Success with presprouting ranunculus
Gardeners know that starting seeds indoors can give you a head start over direct sowing in the garden. Instead of waiting for the snow to melt to put seeds in the ground, we scratch that itch to see green things with a little potting soil, trays and grow lights. It might not seem obvious, but flowers grown from corms can be started indoors as well. Before I was a flower farmer, my only experience with presprouting corms came from gladiolus. My short prairie summers meant that getting gladiolus flowers was next to impossible when planted just as a corm outdoors in May. Most of the older gardeners I knew started their corms indoors (often in an old ice cream pail!) then transplanted them into the garden when green leaves appeared and the risk of frost was minimal. Success with spring ranunculus in our climate follows a similar route, although for different reasons. Ranunculus are not damaged by cold weather like gladiolus are: in fact they love it. The key to getting beautiful ranunculus flowers in my Zone 3 garden is to get them growing as early as possible, before the season heats up. Ranunculus grow best when daytime temperatures are less than 17C and nighttime temps are just above freezing. This is a short window of time most years in Alberta as our spring can be very hot. Prolonged heat causes ranunculus to stop growing, turn yellow and die back. To avoid losing my plants and potential flowers to hot weather I start corms indoors a month before I expect to plant them in the ground. Here are the steps I take in presprouting: