The first thing you should do when you receive your Ranunculus corms is: don’t plant them just yet! Your corms will look a bit like tiny octopi. They’ll arrive dehydrated and ready to store somewhere cool and dark for the winter, or for our warm region friends, for a couple extra weeks until the weather chills down a bit. Planting time depends on where you live. In zones 8 and warmer, plant your corms in the fall for spring blooms. If you live in a zone colder than 8, with significant stretches of freezing weather in the winter, plant in the late winter/very early spring instead, about 6 weeks before your last hard frost. Soak in room-temperature water for 4-6 hours before planting, and allow a little trickle of water to run into the bowl as they soak in order to increase the oxygen in the water. Plant 5" apart, 1-2" deep, with the 'tentacles' of the corms pointing down. Fill in the holes and compress the soil firmly. Water them well - a good long soak. Stick your Plantgem marker in the middle of the area so you remember where your flower babies live now.
We highly recommend pre-sprouting your corms. Your flowers will bloom a couple weeks earlier if you plant the corms pre-sprouted rather than directly after soaking. Also, you can be sure you’re planting only viable corms. You’ll need a flat-bottomed container, ideally plastic, like a seed tray, or even a Tupperware storage container. Start by washing it really well with warm soapy water and rinsing thoroughly. Then, add a layer of fresh dirt, about 2-3” deep, and lightly moisten it with water. (A spray bottle is useful, so you don’t soak the dirt - you just want it damp). Soak your corms as directed above, then place them gently into the soil, making sure they are not touching. Cover them completely with more damp soil. Cover the dirt completely with another tray, or anything you can find that will apply very gentle weight to the soil. (Really, really gentle - you don’t want to squish the little guys - think towels, a folded tarp, etc.) Store them somewhere completely dark and dry, that stays between 40-50 degrees, and where critters can’t get to your corms. (A tricky place to find, we know. Basements, garages, and attics are all good options). You’ll want to give them 10 days to 2 weeks to pre-sprout. Check on your corms every 3-5 days and remove any that are growing mold or looking/smelling funky/rotting. Spray with more water if the soil is dry. Once you see little white hairs sticking out of your corms, it’s time to plant them!
Ranunculus prefer healthy, well draining soil. Enrich with compost for happy plants. They like cooler climates and gentle warmth. Plant them where they get 6+ hours of sun in cooler regions and afternoon shade in hotter regions. Begin to water when you see the sprouts poke up from the dirt. Find the balance with watering them. Too wet and they will rot, too dry and they will wither. Stick your finger in the dirt to check the moisture level before you water. The dirt should be moist. If it’s dry and crumbly, increase your watering schedule. If it’s quite wet (and maybe even stinky), water less.
Prepare to be in awe. Each corm produces an abundance of flowers, and their bloom season is 6-10 weeks long, from early to mid-spring. Stems last up to 10 days in a vase. They are total show-offs and we love them for it. Cut back the withered foliage once it turns yellow in the summer - wait as long as you can, so the corms can store up as much sunlight power as possible. If you are in zone 8 and colder, you can dig them up, dry them out for a few days (in the sun or inside where they can lay out) then store them in a cool dry place. For zones 8 and warmer: just leave them be. The flowers will come back again next season like magic, just you wait.
Plant your corms in healthy soil, then resist fertilizing - they don’t like too much. Pull weeds from around the base. Ranunculi, like so many lovely flowers, are prone to fungi (powdery film) and bad bugs. Protect them with neem oil spray or a veggie-safe anti-fungal+anti-pest product. Gently rinse the foliage in the evening or when it is in the shade, and let it dry before applying. If you know a frost in coming, cover your planting area with a frost cloth.