Growing Ranunculus (Zone 6b, NJ)
To sum up my 2023 ranunculus season, it was pretty much a failure. For the amount of corms I started and the time, investment in frost + shade cloth, I had a pitiful amount of blooms to show for the effort. Not early enough to sell at my florist co-op market, stems not long enough to use alongside my other flowers (ie foxglove), and too short of a bloom time window to truly use them. Instead, they are being given as “bonus posies” for my CSA customers who at least will surely enjoy them. Here is the Youtube Video explaining my experience:
Here are some notes from my experience this year and tips/advice from fellow Youtube watchers.
When to start ranunculus?
In NJ and in parts of the US where our last frost is sometime in May, it is common to start ranunculus in mid-January to early February. I soaked my corms on Jan 30 this year and would definitely move this up by a couple of weeks next year. In some ways, I think the when is less relevant (assuming you start them within this 3 week timeframe), but how you nurture them and when / where you transplant them is more relevant. I saw blooms in 100 days but other Youtube watchers saw them within 90 days. The main difference was fertilizing and where they planted those corms (more below).
Where to plant?
There was a bit of an ah-ha here for me here. Ranunculus love the sun but hate the heat. This becomes a conundrum especially as we enter into early spring. This April, we had a 3 day heatwave of weather in the 80s. Another week, it stayed in the 70s. Other parts of the country experienced similar heat. This problem compounds in May as the days get longer (ranunculus are short-day crops), so it is a battle against the heat and light duration.
My flower field is basically full sun. I wouldn’t plant the ranunculus outside of my fenced field as I already have rabbit pressure IN the field and I know the deer would happily chomp away on them, but I would be more mindful in intercropping.
Youtube watcher grew sunflowers alongside her ranunculus. The ranunculus helped offer some protection from pests and as the sunflowers grew, they offered shade to the ranunculus
Another English YouTuber (market flower grower) grows all of her ranunculus in very large pots close to her shady patio
I could also plant the ranunculus next to overwintering flowers that could provide a canopy- things like yarrow and feverfew which get super tall are good candidates. I would plant the ranunculus where they get morning sun but are shaded out by the canopy of the other crops in the afternoon
There is a fine line between providing enough shade but also enough sunlight. Remember, ranunculus prefer full sun! One Youtube watcher experimented by planting her ranunculus in pots next to a big magnolia tree which means they received 4 hours of afternoon sunlight. The foliage is rich green but they have yet to bud
I think it’s worth putting the last succession into the “shadiest” area. Another learning this year was that the heat tends to blow open the ranunculus so that the center is exposed. The most desirable sellable stems are those with multiple layers and a closed center. In areas where I did not have shade cloth, those buds all had open centers. Another Youtube watcher confirmed that the heat similarly impacts dahlias.
Overwintering vs. Not Overwintering (Zones 6 and above)
The answer is an obviously clear yes to me here - for both. You need to overwinter to achieve the longest duration of blooms (potentially starting in late March) but you also need to start corms in the new year to achieve later successions. The blooms WILL putter out if you don’t start new successions.
The main question is- how to overwinter without a structure?
Jennie Love suggests constructing caterpillar tunnels
Youtube watcher (very close to my area) overwintered in raised beds with hoops and AG-19 frost cloth
My fellow local grower friend just let her 2022 corms overwinter in the bed and achieved blooms in late April. This is what I plan to do- leave my corms in the same bed and see what happens for Spring 2024. Note she did not cover the bed and I think if she did, she could have achieved blooms even earlier!
Blooms achieved by Blute Bauer by leaving the corms in the ground. We did have a mild 2023 winter though!
Fertilizing
I am notorious for being an underfertilizer and it is largely due to my maniacal quest to create such great soil that I don’t need fertilizer! I know this sounds ridiculous but I’ve read that whether it’s organic or artificial fertilizer, the plant doesn’t know the difference and fertilizing makes it less likely for the plant to want to “work” symbiotically with other life in the soil to exchange nutrients and food. I have gotten away with not fertilizing the majority of the varieties I grow but I have come to learn that ranunculus may not be a variety suited for that mindset.
In any case, everyone who achieved successful blooms this season had one thing in common. They fertilized heavily.
Dave Dowling has said multiple times that ranunculus are heavy feeders. Many online fertilize with Neptune’s Harvest, an organic fish/seaweed emulsion fertilizer
Youtube watcher used blood meal (to keep rabbits away) and fertilizer with high phosphorus content. This makes sense to me as the blood meal would have provided more nitrogen for strong leaf growth and the phosphorus for the buds
The importance of cover (frost & shade cloth)
The weather will continue to be all over the place going forward and if anything, may be even more extreme in the years to go. So for me, the answer is a resounding yes to needing both, even if you’re not overwintering.
Frost cloth will undoubtedly be needed if you’re overwintering but even the early days of transplanting may require frost cloth. AG-19 seems to be the cloth of choice. AG-19 is used for general frost protection and is among the more affordable options. It allows 85% light transmission and is good down to 28°. There is also AG-15, 30, 50, and 70. The different numbers denote the thickness and light transmission. The heavier weights (high numbers) offer more frost protection, but they also raise the temperature under the row cover during the day and decrease light transmission. You wouldn’t want something like an AG-70 bc… ranunculus love and need light!
Shade cloth is something new that I added to my arsenal this year and I bought it FOR the ranunculus. It can definitely be used on other crops but besides offering cooler soil temps where covered, it also helps elongate the stem length. I estimate that shade cloth bought me an extra 3 weeks and allowed me to achieve SOME blooms vs no blooms.
Takeaways:
Ranunculus is a tricky crop because it’s not meant to be grown in most of the areas we live. It’s native to the Mediterranean where the springs are cool and wet but the summers are dry. It’s difficult to replicate these conditions without a structure but still possible.
For the beginner flower farmer, find the cheapest corms you can procure. Don’t go off buying the fancy Italian, Romance or Butterfly varieties. Such corms can cost anywhere from $1-$5 each! You should be able to find corms on clearance at year end. In my view, corms anywhere from 20 cents to 45 cents is reasonable as a learning experiment. Once you are able to grow ranunculus successfully with these cheaper corms, then you can “graduate” to the more expensive corms.
Another note about the more expensive varieties- do you have a market that appreciates the expensive varieties? If you’re selling at a farmer’s market or general retail, my general guess is that the average customer is not going to know the difference between an Aviv ranunculus vs an Italian ranunculus. Both will be appreciated but one will set you back alot more in terms how much you paid for the corm!
If you enjoyed this content or this content helped you, consider joining my Patreon where I’ll have more content like this, exclusive for my members. Help me experiment and see what works and doesn’t work so that you can learn from me!