Ranunculus: The Goldilocks of the Flower World

Ranunculus are stunning flowers that remind me of fluffy, marshmallow clouds. They are a garden challenge well worth the extra effort that goes into growing them. In this rendition of Goldilocks, I will share the not too cold, not too hot, not too wet, not too dry, tips and techniques to getting beautiful spring blooms.

Salmon and Pastel Amandine Ranunculus

Fall Prep: Take a Walk through the Woods

Here in zone 6, ranunculus would need quite a bit of protection to make it through the cold, wet winter months. Although possible, it is not worth the effort of maintaining a low tunnel, deterring munchers like voles, and monitoring temperatures to keep them happy. Instead it is better to prep your planting area so that when you are ready for early spring planting, you can just pop your plants into the ground. Having a space that can be protected in the event that we get a late spring freeze is important. A raised bed that you can cover with plastic or frost cloth, a deep crate or planter that can be moved to a protected area, or a garden space that becomes workable sooner than other areas in your yard are all possible options to consider. I use raised beds that have metal conduit bent to create a low tunnel. Plastic, frost cloth, or shade cloth (important for surprise hot weather) can be attached to protect the plants. Although none of this is necessary, this will give you the ability to control some of the conditions required for ranunculus to bloom on long strong stems.

Bed Ingredients to Consider
-Feed the soil: top off the bed or planting area with compost, worm castings, fall leaves, alfalfa pellets, or other addition that will break down over the winter
-Vole deterrents: oyster shell (we give this to our chickens and I steal it to mix into the ranunculus bed) mixed into the top layer of the soil helps deter voles from tunneling, garlic planted around the edges of your planting space will also deter them, barn cats (success of this measure has yet to be determined), wait as long as possible (early February for me) before warming up the soil with plastic, and finally, traps if absolutely necessary to save your plants from utter destruction (trust me, I’ve been there)
-Calcium: many weak stems can be associated with low calcium in the soil. Oyster shell and egg shells release small amounts over time but for me, not enough so I always give my plants a feeding of CalMag or in a fun experiment, you can make your own calcium amendment using crushed eggshells and vinegar, I used Jennie Love’s recipe, very cool for the kids and I to observe.

I can’t say it enough but PREP your space. Now let’s say you didn’t know you were going to be planting these finicky corms (yup, those shriveled octopus shaped things are called corms) and you just so happened to grab some because the flowers on the bag look too enticing to pass up. What can you do? Grow in a larger container or crate where you are better able to control the growing conditions or wait a bit later in spring to plant out when you can mix in some of the above ingredients. If you plant out later, consider a location that gets morning sun and afternoon shade. This will help keep the soil cooler longer so they have a better chance of flowering.

Porridge: Soaking and Presprouting

It is now late winter (January and February), you have just bought a bunch of dried and dead plant matter, and you are wondering how they will turn into the beautiful flowers you have seen in photos. Time to start the soaking and presprout process! It is possible to place the corms directly into the soil but it will take longer for them to get going and there is a greater chance that something could go wrong.

Soak corms for about four hours in not too hot and not too cold water. I leave the water on at a trickle to continuously introduce air into the bucket which keeps that water from getting stagnant or providing bacteria a chance to grow. A fish bubbler is also a great way to keep the water moving.

The corms should plump up and now resemble healthy octopi.

Drain the water, grab some trays (takeout containers, 1020 trays, or other vessel a couple inches deep), and some seed starting mix (I use a blend of promix, coconut coir, and worm castings. Add water slowly to your soil mix until it is damp. When you squeeze the mix, very little water should drip from your hand. The corms will continue to grow and absorb more water as they begin to sprout. Again, not too wet and not too dry! Layer soil on the bottom of your container and space your corms out so they are not touching but still close, why waste space? Also keep the corms from touching any of the plastic as this can cause corms to start rotting. Place soil on top of the corms and pat down so that they are snug and corms are not peeking through. Cover the whole container with a tray cover, another tray, or plastic wrap and place in a darkish spot. Leave them in a cool spot (55-65 degrees) for a few days and then check back in.

When you check in with your corms, you are looking for three things:
1. mold spots (white hair growing on top of the soil) that may indicate a rotting corm. Take out any rotting corms immediately so it does not spread to other healthy corms.
2. dry soil, mist with water until slightly damp, DO NOT OVERWATER
3. Growth! Cracks in the soil will lead to small white volcano like growth and small white roots and this is what you want to see.

Find A Comfy Chair: Growing on

The corms have started to grow! Roots and small tips are pushing out and reaching for light. It is time to move those trays or containers to a light source. This could be a greenhouse (ideal if it is minimally heated and vented to keep the corms between 32 and 60 degrees), grow lights about 2-3 inches from the top of the sprouts, or outside if the temperatures allow for it. The more exposure to cold that the corms have, the better their root development and the hardier the plants are.

Ranunculus can withstand short periods of cold, as low as 20 degrees (sometimes more), as long as the corms themselves don’t freeze. They actually prefer the cold and will start to go dormant as soon as the soil temperatures reach about 70 degrees. This is why it is so important to pay attention to the temperature. I have found that the ranunculus grown outside in the greenhouse where it drops to 34 degrees at night and no higher than 65 degrees during the day improves their hardiness when placed in the ground and also encourages low growth that will protect the leaves from wind and frost when placed outside. If you choose to grow under lights inside, make sure the ambient air and soil temperature is less than 65 degrees. Another option would be to set your tray or container outside in a protected area on days that it is above 32 degrees and back inside when the temperature drops below 32 degrees. This is a lot of work! If this doesn’t sound appealing and you have your grow space ready to go, then get those little sprouts into the ground. They may take a bit longer to get going but it may be your best choice. Again, the soil needs to be workable and you may need to add protection if there is a cold stretch of weather. If you plan to plant outside, you may choose to start your corms a bit later in March.

Look for a Cozy Bed: Planting out

Corms should be placed about 6-9 inches apart depending on whether you plan to add companion plants. I use tight spacing because I want to fit as many as possible into my raised bed.

Offset planting allows for perfect planting spots between the corms. Stock, silver tip wheat, cress, and giving saponaria a try this year are companion plants that have been successful so far.

In the photo, you can see the hoop/low tunnel set up along with the close spacing of the ranunculus. In this bed, I have little stock babies planted between the corms.

The Nap: Waiting for Blooms

Your corms have sprouted and it is time to wait for those blooms to set. While you wait, there is no napping allowed. These plants need food (Neptune’s Harvest, worm tea, compost tea, calcium you made) every other week for strong plants. It is also a good time to monitor for voles as these are very tasty treats just waiting to be munched. Look for tunnels, leaves pulled toward the edges, or corms completely dug up.

Water during dry spells as they do require a good drink now that their roots and leaves have formed. The water will also help the soil from warming up too fast. During hot days, shade cloth, a good watering, or planting where the plants receive shade in the afternoon will help extend the bloom window of the ranunculus. I’ve also been known to ice my plants, not so sure it worked though. It will take about 90 days for the buds to start showing up. They begin at ground level and push their way up. My experience is that days to bloom is important but so is the number of daylight hours. Predictably, at 14 hours of daylight, the buds will begin the stretch upwards. For me this is the end of April so no matter how early I start my plants, there will be no buds until the end of April and the first blooms starting the second week of May (just shy of Mother’s Day…).

Wake Up its Party Time!

Didn’t you know Goldilocks invited Little Bear to her birthday party where she gave out ranunculus favors to all the guests! Hmmm, maybe I’m making up the ranunculus part but she did have a party if you ever read The Jolly Postman as a kid.

It is time to harvest or simply enjoy all the effort you put into making these flowers bloom. They are showing off their color and petals and if you give them a slight squeeze, they feel like a marshmallow.

This is the perfect time to cut the flower and bring it inside to enjoy. Ranunculus prefer only an inch or two of water in the vase and would love a stem trim every other day. With clean water and trimming, ranunculus have a long vase life and can last up to two weeks. Keep cutting the blooms from the plants until the weather turns hot and they go dormant. This could be very quickly if we have a short spring or could last until June if it stays cool. When the corms die back and turn yellow, you can then dig them up, wash them, and store them in a cool, dry location until the following year.

Trouble Shooting and Companion Plants

Corms are rotting- too much moisture so add in some dry potting soil to absorb some of the extra water
Corms aren’t doing anything- most likely the soil is too dry and they haven’t got the motivation to do anything yet. Also, make sure it isn’t too warm as they will remain dormant.
Aphids- try planting a trap crop with your ranunculus. This could be nasturtium or silver tip wheat (my go to for both trap crop and spring bouquet addition)
Voles- terrible problem, see above suggestions and also consider repellents, or 1/4 chicken wire under and around planting space.
My ranunculus didn’t bloom- most likely they got too hot before they could set their buds. This is why a long cold period is essential for blooms, investing in shade cloth or planting in a part shade location can help extend the bloom period.
Stems toppled- this could be calcium deficiency, try adding calcium into the soil with regular feeding.
Deformity- on occasion, the bloom or stem or both can be misshapen which could be a variety of different things including disease or fasciation
Spring Companions- stock, silver tip wheat, garlic, cress, and spinach are all good companion crops. New experiments for this year include godetia, saponaria, and larkspur.