Time to Reap the Reward
It’s finally here- the dahlias are starting to come in. It begins as a slow trickle, just a few handfuls one week and then it gets more the next, then it jumps and we are cutting buckets before I know it. We aren’t quite to the buckets point yet but we aren’t far off. I look around the field and see more and more organza bags protecting our precious buds and I know it’s coming!!
So how about a harvesting tutorial? (I’ve got a special tip in here for all the flower farmers too!)
Knowing the correct stage to harvest is important with dahlias. There’s a myth that says they don’t open anymore after harvesting. But most varieties I know will open at least about 20% more after you cut them. Knowing this makes it important to know the proper harvest stage (that’s also really important for good vase life too!)
Harvesting:
Know what application you are harvesting for. I harvest for cut flowers for florist wholesale. This is a bit different than if I were cutting for a dahlia show or bouquet/grocery store use.
This is Sweet Fabienne pictured above. In the far left photo is the correct stage for bouquet/grocery use. You want 2 rows of petals beginning to reflex backwards. For florist use, I would cut more like the 2 middle pictures. They like their blooms more open and at the perfect use stage. Most of the blooms they buy from me are used within 2-3 days so as open as possible without having a blown center is perfect for them. The last picture shows the frontal view of picture #3. It’s a good full dahlia. Picture #1 will look like this within 2-3 days of sitting in the vase but since vase life is so important for bouquet use, you want to cut it earlier to give your customer the full show!
2. Stem Length- We measure with our arms. Our minimum stem length is from finger tip to elbow. Anything less than that gets culled. Goal stem length is mid bicep. I’m often asked if you should cut at the first node below the bloom so that they side buds will bloom. This doesn’t work for cut flower use- too short. If your goal is as many blooms as possible for a stellar display in your home garden- then deadhead spent blooms at the first node (break) below the bloom. But for cut flower use- if you want long stems, you have to cut long stems. Sequential stems will always be a little shorter than your original so if you want them long, you have to cut long from the beginning. It may feel like you are taking half the plant at first but it will push more longer stems if you cut deep.
3. Consider the form of the dahlia. Different forms require different cut stages.
From Left to Right:
#1 Bridezilla- I find this one looks best if the first row of petals has started to reflex. It will open to a nice fluffy state.
#2 Cactus Types (this is Clearview Jonas)- These look much better if you let them open a lot - But you want to make sure that center is still tight. But their true beauty is in the layers and layers of petals they have that give them a full look.
#3 Cafe Au Lait- this beauty can be cut fairly tight and still open well. Ideal stage is when she has a flat back. Make sure her center is still tight and not showing any yellow pollen.
#4 Peaches N Cream- She has such a good vase life that you can cut it more open and it will still last really well in the vase.
4. Know your varieties- As you’ve just seen in the pictures above, you can get the best performance out of your dahlias by knowing your varieties. But to do this, you have to test them. So always cut, put in a vase and observe. Take photos- I find this helps me remember.
Now- A tip for the flower farmers. We are using a new system this year to help us remember how to cut each dahlia at the proper time. I made labels for each variety and tagged each row.
The harvest stage listed refers to the harvest stages for dahlias in the Floral Standards book put out by the Seattle Wholesale Growers Market. So now all we have to do is learn the 5 harvest stages listed in that book — Instead of remembering the harvest stage for 100+ varieties of dahlias! I plan to print out a small poster of the 5 harvest stages and post it in our field pavilion.
Your Dahlias Need a Therapist
The other day one of my crew members asked why do dahlias get green centers? I explained it was a sign of stress. She responds with: “Poor little dahlias, they just need a therapist!”
Some days I feel like a dahlia therapist- there’s a reason my Instagram is called “Flower Therapy”. One of my goals in life is to show people that growing can be fun and not stressful. Gardening should be a form of therapy - there have been so many times in my life where it has played the role of therapist- good and bad times!
I feel like I’ve gotten more panicked emails from growers this year. Not sure if the weather is worse or why exactly. I do know this- there are a lot of brand new dahlia growers who have found their way here. That makes me really excited! If it’s your first year, you are in the right place!
Today, I want to normalize some things for you. I hope in the future that new growers will find this post and realize there’s no need to panic!
No particular order here but I want to explain some things — these are all drawn from emails/questions I have received from new growers this season.
1. Green Centered Dahlias- As stated- stress is usually the cause. In particular heat stress. During a hot summer, a lot of dahlias won’t open well and they tend to push a big green center as a heat response. It is possible that genetic breakdown can be the cause of this too but if you are in a hot climate, it’s usually heat. Once the weather cools in the fall, it goes away.
2. What do you do if a plant falls over or breaks off? Clean up the break if it broke off and you’ve still go a plant left- cut back to the next node. Make sure to keep it watered and fed and it will grow back. Falling over is lack of proper support- and learning how to support your dahlias takes a few seasons. Stakes, tomato cages, netting are all good options.
3. My dahlia rotted. Losing a few dahlias each year is par for the course if you grow in a hot climate. Loss is normal and should be expected. We lose 15-20% of our plants every year- usually to too much rain or too much heat. There’s only so much you can do about it- best thing is to observe what happened and try to fix it for the future.
4. I’ve got these white spots all over my leaves (especially in June/July). Most likely you have thrip damage. See the picture below. A good pesticide will take care of it- Capt’n Jacks Dead Bug Brew is an organic option that I like. You’ll need to keep up a regular spray schedule for a month or two until the thrip pressure lessens in your area.
5. My leaves look stippled and are starting to yellow. You’ve got spider mites or broad mites (maybe both). The Capt’n Jacks will work if they aren’t at infestation level yet but if you need something stronger- Avid is a good option.
6. My plant is gorgeous and green but has zero bud or flowers (asked in June). Hang in there- dahlias put on their show in late summer and fall. If you see people with earlier blooms, they probably overwintered their plants.
7. Half of my bloom doesn’t seem to want to open. This is thrip damage again. Thrips can cause this distortion and also turn a light colored bloom brown overnight. They are tiny brown bugs- visible with a magnifying glass. Organza bags have worked well for keeping the thrips off the blooms. You must put them on before the bud begins to open.
This is not a complete list by any means but I hope it will normalize some things that happen to all of us. There’s no need to panic and maybe you can avoid taking your dahlias to the therapist.
Prepping- Dahlia Style!
We’ve been in the middle of a heatwave like most of the Southeast and a large part of the country over the past week. Through the years I’ve learned a few tricks to combat the effects of heatwaves. Today I’m sharing what I did late last week to prepare for the heat wave.
The first thing to consider is what stage of growth your dahlias are currently. For example, I have a field of very small rooted cuttings that was planted out a week before this heat wave. Not great timing, I know. But it couldn’t be helped. We had reached the “now or never” point in the season and it all had to get planted. But I knew that left alone, those little cuttings would have died. So I remembered that I had a large piece of shade cloth ( this is a piece that fits a farmers friend hoop house). I have safety caps on top of my support posts so I knew we could just drape it over that field without ripping it. It took us about 20 minutes from start to finish. Easy peasy!
The other thing I did for this field was add mulch- we had a lot of rain early in the season and it washed off a lot of our mulch. I also made sure it got extra water for any day during this heat wave that we didn’t get rain. So far— they are looking pretty good!
Second major task we did was to use the “dahlia sunscreen”. This is the Surround spray - (kaolin clay). This spray will help with bug prevention but it also will lower the temperature around your plants. I can only use this for the first half of the season. After we pinch, I stop because I don’t want it on the stems/blooms I’m selling. It doesn’t wash fully off. Luckily we had just pinched the plants so I was safe for one more spray. A week later and I would have been out of my window. (the picture below was taken after 2 big storms had come through, so some has washed off)
Third thing I did was a little cutting back. I had 2 rows of 3rd year dahlias that needed to slow down a little bit. They were blooming too early and the petals were burning in the extreme heat. So I cut them back by around 60%. Now I’ll confess I did this the day before the heatwave started. I don’t recommend that— try to pay attention to the weather and do this several days before your heatwave. But they are okay. It was better that I did it, even though my timing wasn’t the best.
Lastly, another technique that I used partially. I used a sprinkler to overhead water everything on day 1 of the heatwave. I wanted to add extra water but I also wanted to bring up my humidity levels in the field. Raising those will help prevent powdery mildew. PM and spider mites love to reek havoc when it gets hot and dry. I would have continued the sprinkler at least every other day but we got rain (surprisingly) on days 3 and 4 of the heat wave.
Those are just a few of my tricks from many years going through heat waves. We always get a few but as long as your plants are well established and you keep them irrigated well- they usually make it through!
Wilty Dahlias
Are your dahlias sad? Do they droop and sag? You’re not alone! Unfortunately dahlias don’t always look happy and healthy- especially when growing in a hot climate.
So let’s talk about some of the possible causes:
We’ll start off with the obvious: Water— either too much or lack thereof
1. So if a dahlia wilts, the most likely thought is- It needs water right? Well that’s the first thing I check. Stick your finger down 1.5 inches into the soil and test the moisture level. If it’s dry, then it’s a good chance it does need water. But it’s also worth checking a few other things!
2. I always try to feel down to the tuber- you want to make sure it’s not rotting. If it’s rotting, then this is more likely the cause of the wilting. There’s not a ton you can do if it’s rotting. If it’s early enough in the season, I try to grab a cutting off of it. Or sometimes I will cut the plant back a little bit so that the tuber isn’t supporting so much green growth. But in reality these are last ditch efforts- you are probably going to lose it.
3. Now if the tuber is firm and the soil is moist - well that leads us to the next possible cause:
Verticillium Wilt- This is a soil borne fungal disease. It prevents water from moving through the vascular system - therefore showing up as wilting, yellowing foliage and dieback. There’s not a lot you can do unless you catch it really early. Sometimes you can chop the plant back hard and it will recover but you have to catch at the first sign of wilt. The problem is that it usually affects the plant in the lower portion of the stem and blocks water flow to the upper parts- which is why it’s so hard to deal with. Don’t compost any plant parts that you remove.
Prevention can help but it’s not a sure way to keep it away. Using a fungicide spray regimen before you see any signs can help prevent it or slow the onset. Soil solarization where you find it can be helpful too. But unfortunately, it’s usually a death sentence if you catch it too late.
Browning Leaves and Black Tips on new growth are also commonly seen in wilty dahlias. The browning - if it’s seen higher up on the plant is usually a sign of sun scorch. Lower brown leaves- like around the base of the plant may be signs of fungal issues. Black tips on new growth near the top of the plant are signs of a boron deficiency (Cafes love to get this!).
Next time you see a wilty dahlia, you know where to start to diagnose the problem! Want to be the first to know when we release a new blog post—
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The Radish Experiment
We grow a lot of our dahlias at an offsite plot and the owner of that plot has chickens. During the winter we often use daikon radish as part of our cover crop. Turns out that the chickens love the radish greens.
Well obviously they disappear once we terminate our cover crop so I decided to try an experiment so the chickens can have more radishes (and hopefully keep some weeds down) Anything for the chickies!
We have 2 rows of dahlias in this plot that are planted 2 across in a 4’ wide bed instead of the 4 across that we usually do so those rows tend to get very weedy on the edges.
These are the hurricane survivors by the way. It took them awhile to get going but they look great now!
So I went to my local feed and seed and bought a pound of radish seed and sprinkled a row down the edge of the bed. I seeded pretty generously so that there would be enough to help cover the soil and prevent weeds. But also so we could have enough to pull to feed the chickens.
We got a great rain the evening after I sowed these so hopefully in a few days, we will see little radish sprouts! I’ll keep you posted.
Update (7/23/25)- Radishes germinated well but I definitely need to work on seeding evenly. In the left picture you can see a 10’ stretch of row and how it’s a bit sparse in some areas. The right picture shows a close up of a well seeded area- This is what I’m going for. I reseeded after I took these pictures and we had good rain yesterday so hopefully the second time works!
