Pre-sprouting ranunculus & anemone corms
If you want to grow ranunculus and anemones, especially as a professional cut flower grower, pre-sprouting corms are one of those “aha” tasks.
It’s a game-changer.
It’s amazing.
If you want to learn about it, you are my people! In our last post about growing ranunculus and anemones, I discussed pre-soaking corms in detail: “You need to wake ‘em up by plumping ’em up”! If you missed that blog, you can read it here or watch the video below!
Before pre-sprouting, pre-soaking the corms is a must-do step since you need hydrated corms to initiate the process.
Once you’re caught up, we are ready for the second step towards having a successful ranunculus and anemone crop come spring, pre-sprouting corms!
Whether you are one of the cool kids with a large greenhouse or high tunnel or just a humble field-grown grower (like me!), pre-sprouting ranunculus and anemone corms will result in some beautiful, healthy blooms.
A lot of growers get nervous when it comes to growing ranunculus and anemones. I don’t blame them! They are a heftier investment than an envelope of seeds. The stakes are higher! We prefer to purchase fresh corms each season, especially since many of the fantastic varieties are patented anyway, but also to better avoid disease. Corms can be an expensive annual investment, much like tulips.
The good news is that these plants are tougher than we give them credit for. They can be successfully grown even in colder climates with some upfront work and protection. These guys are true spring beauties and are photoperiod-sensitive, meaning the long summer days are too much for them. Along with being daylight sensitive, they do not love hot temperatures above eighty to eighty-five degrees Fahrenheit, which will quickly put them into dormancy. They prefer 60F-70F during the day and cool temperatures in the evening.
As stated in my last post, one of the biggest challenges when growing ranunculus and anemones is avoiding root rot. They are super susceptible to this. Many variables contribute to root rot, but they all come down to not-nice bacteria and fungi. Properly pre-soaking the corms is just the beginning of the battle. Another tool to have in your arsenal is to pre-sprout.
Yeah, yeah, yeah, I keep telling you how awesome pre-sprouting is, but what the heck is it?
It's hard to imagine, but it’s just what it sounds like: we will allow the corms to sprout under ideal and controlled conditions before planting them in their growing bed. This is instead of planting the corms out directly after the soaking process.
The pre-sprouting process has more to it than that, which we will get into.
First, why take the extra step of pre-sprouting ranunculus and anemone corms?
Benefits of Pre-Sprouting Ranunculus & Anemone Corms
Why Pre-sprout Corms?
After all, this is another step to take with these already needy flowers. I get it; I’m all for working lean, but sometimes these “extra steps” in the beginning will reward big in the end. This is one of those times.
There are three main reasons why we decided to add pre-sprouting to our corm growing regime:
1. Pre-sprouting saves space.
Through the pre-sprouting process, you can easily weed out the dud corms. This results in you planting only healthy, viable corms, thus saving bed space for the corms that wouldn’t have thrived. No gaps in the planting bed! On any level, space is valuable. That space sucks up resources and isn’t making you money.
This is especially helpful if you want to save your corms to grow the following season. Saved corms tend to be more susceptible to rot than freshly purchased ones from a reputable source because of differences in post-handling.
2. Keeps growing healthy soil.
Since you are only planting the healthy corms through the pre-sprouting phase, you should be able to avoid planting corms that are diseased or infected with bacteria/fungi that could spread to your healthy ones.
This will help reduce the risk of introducing random diseases into your soil by never planting them in the first place. The pre-sprouting process is essentially a pre-screening process as well.
3. Gives you a jumpstart!
If you’ve grown flowers or vegetables in the field, you are well versed in how the weather can vary from week to week. One week of sub-optimal soil temperature or weather can be rough on these plant babies. Ranunculus and anemones are picky, and there is a window of when you can plant these guys successfully, at least in our zone 6b. They don’t like to be frozen, but they don’t want to be too hot, either. If we waited until March to get these guys into the ground without pre-sprouting first, we are at a high risk of not getting a harvest from them before the summer heat makes them shut down.
Getting these guys pre-sprouted in the winter will give us enough time to grow them while their intended beds are still being prepared. Then, once planted out later in the season, they won’t skip a beat! Two to three weeks can mean the difference between ideal blooming conditions for them and crop failure, especially for our later successions.
Overall, we have more control over the corms in the beginning. We can better make decisions about when we want to plant out. We can hold them back if needed due to inclement weather conditions or not having the beds prepped and planting them out when the time is right. We can provide them a much-needed head start that will lessen their chance of rotting by giving them a good, healthy root system to launch with.
Whether planting crops in fall, late winter, or early spring, they benefit significantly from having a healthy root system at transplant time. When the soil temperatures are a little cooler or wetter, sprouted corms will be better able to handle all the curveballs thrown at them during these volatile times of the year.
Have I sold you on pre-sprouting corms yet? I hope so! Now, I’m going to tell you how we do it!
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Now back to the blog!
The Process Of Pre-Sprouting Ranunculus & Anemone Corms
There are many different ways and different substrates for pre-sprouting to choose from: it is not a one-size fits all. Use what you have readily available and what you think will give you the best results.
Supplies Needed for Pre-Sprouting Ranunculus & Anemone Corms
Flat trays, 50-cell propagation trays or air-pruning 72 cell trays (clean and sanitized)
Substrate: quality potting soil, peat moss, vermiculite or coco coir
Soaked corms (and their corresponding labels you put together when pre-soaking)
Water (room temperature or cold, not hot)
A cool, dark place to sprout them, 40-50 degrees F (we’ll talk about what we use!)
Optional: fungicide
Optional: sticker labels and a pencil
When to Pre-Sprout Ranunculus & Anemone Corms
Pre-sprouting should be done as soon as that timer goes off from pre-soaking the corms.
Remember, you don’t want those corms sitting in water too long, but you don’t want them drying out again.
Method of Pre-Sprouting Ranunculus & Anemone Corms
Optional: Treating the Ranunculus & Anemone Corms with a Preventative Fungicide
About the last thirty to forty minutes of the corms' pre-soaking, you can add a biological fungicide such as Actinovate, Rootshield, or Ailette.
After tucking them into the trays, you can prepare the fungicide solution and apply it as a drench to the corms.
This is a preventative step to help lessen the chances of dealing with pythium and fusarium root rots and infections. If you have poor draining soil, are growing in an area with high amounts of moisture, are using saved corms, or have soil with disease issues in the past, pre-sprouting is simple and will save a lot of heartbreak.
Step 1: Preparing Substrate
Bust out your chosen substrate. Lately, I have been loving Promix HP or Fox Farm’s Lucky Dog. Put the chosen substrate in a bucket or deep tray.
Moisten the substrate. Much like seed starting, be sure to have it similar to a wrung out sponge but leaning towards the drier side.
The substrate should not be sopping wet. Add a little water at a time. It’s easier to add more, but if you add too much, you may be waiting for it to dry up or finding yourself needing to add more planting medium.
Note: If you are planning on doing a fungicide drench, have your substrate dry and watered at the end of the process to avoid contacting skin with the fungicide.
Step 2: Preparing Trays
Take your chosen sanitized tray/propagation tray and put in a couple of inches of your chosen substrate.
Note: We invested in Bootstrap Farmer’s 50-cell trays and 72s last year, and I won’t return. The quality of the trays and the results led to a more efficient and high-quality crop. As a bonus, using propagation trays, if a corm does rot, it will remain isolated and not infect the other corms. Use which trays you have on hand or what you prefer, but if you want to invest, I highly recommend Bootstrap’s trays, especially for such pricey corms.
In the past, we had a bunch of trays for holding one-gallon square containers on hand that we used. Since it has holes, we just put down some brown paper bags at the bottom to keep the substrate from falling out. Using what you have on hand is good, too!
Also, you could add substrate directly into the mesh bag and pre-sprout that way. I have tried it, I was not in love, but that doesn’t mean you wouldn’t.
Step 3: Placing Corms
Place the corms in the substrate; be sure to place labels as you go!
Speaking of labels, I feel secure using the plastic labels I put together during the pre-soaking process and sticker labels on the tray. I have kids and pets. They have this thing for plastic labels; a sticker label has saved me more times than I care to admit!
Place the ranunculus corms “carrots down” (because their little legs look like carrots, get it?).
Place the anemones with the pointy side down; think acorn.
Once the corms are placed and labeled, cover them with an inch to two of substrate.
Selecting Pre-Sprouting Location for Ranunculus & Anemone Corms
Tuck your trays into an area constantly between forty and fifty degrees Fahrenheit. Lowering the temperaturerovide slightly slower root growth, to forty will p while keeping it closer to fifty will provide quicker root growth. This is an ideal temperature range to encourage healthy root growth for these guys.
Hopefully, you’re a cool kid with a basement or even a walk-in cooler of some sort. We are not that cool yet. Over the years, we have used the following:
A deep chest freezer and an Inkbird thermometer in hand
A commercial refrigerator
An unheated Garage
Be sure that wherever you decide to pre-sprout, it does not get below freezing and is protected from rodents and other pests.Another thing about the pre-sprouting location is that there should be no artificial or natural light.
The reason?
You want the corms to focus on developing healthy roots, not reaching or searching for sunlight.
We aren’t looking for foliage in the pre-sprouting process, especially if you are planting in a cooler climate. We want nice, healthy roots; the foliage will just get killed back, which won’t necessarily ruin the crop, but it won’t benefit it.
We have had the best results by pre-sprouting the corms in our unheated garage, with trays stacked upon each other (which helps the trays from getting too dried out).
Taking Care of the Ranunculus & Anemone Corms During the Pre-Sprouting Process
Wait. Walk away. Do not check on those corms every hour of every day. They are fine. Check on them every other day or so. DO NOT KILL THEM WITH LOVE! Did you get that?
Only water when the soil is dry.
Don’t judge the dryness solely based on the top of the soil; check further down, where the corms are nestled. These corms don’t like to be soggy. Remember, they are prone to root rot, so stay away from the watering can on a daily basis.
Unless you have the trays left in the open air, you won’t have to water the corms again during the pre-sprouting process. If they are in a garage or something, using a dome lid can help the soil retain the moisture better. Just lift the dome lid occasionally to allow some fresh air in.
We prefer to stack our trays on top of each other. We also live in an arid climate, so we water weekly or every other week.
In about two weeks, sometimes more, sometimes less, depending on all kinds of variables, you should see the corms pushing out some white roots. I like to let most of them sprout and see the roots about an inch long.
A big reason we prefer to use high-quality potting soil for this task is all the lovely perlite. It helps with drainage and prevents the corms from easily becoming waterlogged.
I have noticed that anemone corms take longer to begin sprouting than the ranunculus. If you think about it, it makes sense: they are a lot harder! If you aren’t seeing the anemones growing but your ranunculus is going nuts, don’t panic. The anemones, too, will sprout. They may take a week or two longer than the ranunculus, but once they get going, they go fast! Give them some extra time; they will grow as long as they aren’t molding or rotting.
During the pre-sprouting process, when you check on your corms, be sure to pull out any that have become mushy or rotten. They won’t grow and will eventually infect the other healthy corms.
Troubleshooting the Pre-sprouting of the Ranunculus & Anemone Corms
If…
You are seeing excessive rot, check your substrate to see if it’s too wet. Pulling the trays out and allowing them to dry out some or mixing in additional substrate may help with this. *Note saved corms may be more prone to rot.
There is a little bit of mold on the corm, but the sprout is looking healthy. It is still okay! As long as the corm isn’t mushy, it is viable.
You are seeing a lot of surface mold, then increase airflow.
Since our trays are stacked in a cooler that does not have airflow, every couple of days, I pull them out and rotate them to provide airflow and disrupt the mold’s efforts to grow.
Your corms are not sprouting but still look good: check the substrate moisture.
If it’s too dry, spritz it with a spray bottle or lightly water it. Remember, don’t soak it completely!
If the substrate's moisture level seems good, check the location. It may be too cold for the corms. Place them in a warmer location that maintains about 50F.
What to do if You Have to Delay Planting Out the Ranunculus & Anemone Corms?
You have two options to handle a situation like this if you can’t plant due to weather, temperature, or life. Trust me, it is better to do one of these options than to try and plant in the mud or during a cold snap.
Option 1: put the sprouted corms in the greenhouse and start greening them up. I’ve done this, it works. I will caution that sometimes letting them get too cozy in the greenhouse can lead to more shock once planted in the field or an unheated hoop house. All those excellent leaves could get nipped by the cold, even once adequately hardened off, but don’t freak! New growth should come and save the day. Ensure the greenhouse doesn’t get too warm for the plants; ideally, it should be below 70F.
Option 2: stick the sprouted corms at the bottom of the cooler or the coldest corner of your basement without light. You don’t want them frozen, but if you're going to stall their growth, you can keep them at about 38F-40F. Even allowing some dipping down to thirty-seven won’t hurt them. The cold will slow them down and buy you a few weeks to plant them.
Pro-tip: When the weather cooperates, prep their row ahead of time and pop a low tunnel over. That way, the soil keeps from freezing, is ready, and shouldn’t become waterlogged.
I hope this gave you a little more confidence and leg up in your ranunculus and anemone growing game. If you haven’t grown these spring beauties or have but not incredibly successfully give pre-sprouting a whirl.
Until next time, we are looking forward to helping you hand blooms soon!
- Jessica & Graham
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