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Home Blog FLOWER FOCUS: Growing great Dahlias {part 1}
February 24th 2014

FLOWER FOCUS: Growing great Dahlias {part 1}

Written by
Floret

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I get asked all of the time what my favorite flower is and answering always feels a little like singling out a favorite child. In truth there really are no favorites, just preferences at a given moment depending on circumstances like the mood that day, what’s peaking in the garden, the weather and so on.

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But in August and September you’ll rarely hear any other answer to this question than Dahlias. Dahlias, dahlias, dahlias…. last summer we grew 3,500 and this year the plan is to double that.

During the long, hot summer stretches I often dream about them, counting to fives, rubber banding their stems and placing them into water. Over and over again. Many late summer days are spent entirely in the dahlia field, from sun up to sunset harvesting and bunching, driving truckloads back and forth to the cooler. On dahlia harvest days we are all ready for the change of pace and welcome the monotonous, beautiful, steady task that it is.

Floret dahlias
 
We’ve tried numerous approaches and techniques to growing our dahlia crops over the years. Here I’ll share what all of that trial and error has boiled down to but please keep in mind, this is what works for us, in our climate and based on our own personal production goals. We have severely limited space so must grow our plants closer together than we would if there were huge rolling fields at our disposal.

We also grow our flowers organically, so I won’t be recommending a bunch of chemicals but instead what we do to preventively combat insects and disease. Some of it may sound a bit “woo-woo” but the approach has worked very well for us and I think it might for you too. If you have any tips or tricks that you’d like to share (organic or not) feel free to leave them in the comments section below. It’s always nice to hear what others are doing all around the world.

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90% of our dahlias are grown out in the open field. Our little plot is situated on top of a sandbar, literally. If you dig down just a foot, you’ll find silver beach sand, so we rely heavily on large doses of compost for fertility and thick mulches to help retain moisture through the drier parts of the season. We generally begin field planting about two weeks after our last frost date (4/25) with the process normally consuming the early part of May. Prior to planting all beds are amended with 3-4” of compost, rock phosphate, a little lime and a general organic fertilizer.

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This mix is tilled in and then tubers are placed roughly a foot apart down the row, with two rows per three foot wide bed. Dahlias need a lot of water throughout the season. We run three lines of drip irrigation per row and then mulch over the top of it with a thick layer of leaves or dry grass clippings to help keep the water from evaporating. While this process is very labor intensive, once the tubers are in, dripped and mulched we do very little to them for the remainder of the season.

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When sprouts begin to emerge, we go through and pull back the mulch from around the crowns. Once the plants reach rough 12″ we give them a hard pinch (snip out 3-4″ of the growing center) which encourages low basal branching, increased stem count and overall stem length.

We then start applying a bi- weekly doses of compost tea (with added kelp, rock powders and fish emulsion) to promote strong growth and help combat disease. T-posts are placed every ten feet on the outside of the beds and a double layer of bailing twine is attached to corral the bulky plants. In past seasons we’ve used tenax flower netting to help support plants but getting it off at the end of the year was a nightmare so we switched over to the twine.

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For big fluffy, fragile blooms like those of the dinner-plate group, we’ve recently changed over to growing them indoors. This tiny tweak has made a world of difference in both productivity and stem length, but flower quality has also shot through the roof! Tender monsters like the Cafe au Lait’s really benefit from being out of the weather. Our plants reached over 7ft. inside the hoop-house and that was with twice a week harvesting!

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Next season the plan is to use a sturdier support system (wire mesh instead of the twine) to help corral their incredible bulk. Pinching low is essential for useable flower stems on these beasts! Trying to get a dahlia with a stem as thick as a broom handle into a bridal bouquet or centerpieces is a nightmare. Our hoop-houses are unheated but with the extra insulation we were able to tuck tubers into the beds by mid March.

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Insect pressure varies from season to season. Some years aphids come in abundance, other years like last thrips are a big issue and earwigs, those little bastards are always lurking, ready to chomp the perfect blooms. We’ve found that the healthier the plants, the less insect pressure we experience, so we do a lot of work to keep plants healthy and well watered throughout the season. Just like the human body, the stronger our immune systems, the easier time we have fighting off intruders.

In really extreme cases of aphids we have resorted to a few application of insecticidal soap to knock back the population. Safer brand makes and OMRI approved concentrate that you can find at most garden and hardware stores. Because of on going western flower thrip pressure, we’ve stopped growing white dahlias in the field and instead have better luck with them indoors. I’ve read about a few OMRI approved options that we might test out in the near future but so far, nothing has been very effective.

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In the hoop house especially, earwigs wreak havoc and we’re still trying to find a good solution. Someone suggested last year that laying out pieces of plastic irrigation pipe with one end taped off would lure them in. Then in the morning you sweep through the patch and empty the pipes into a bucket of soapy water. We got so busy last season that I didn’t give it a proper go but am determined to try it again. There’s nothing more heartbreaking than seeing dozens of Cafe au Lait blooms chomped into bits!

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While dahlias aren’t a terribly long lasting cut flower, their brilliant colorful blooms make up for their fleeting existence. The trick for longest vase life is keeping them well hydrated from harvest to the end consumer and to cut them from the plant at the proper stage. We harvest our patch every three days, rain or shine and never leave a single ripe flower on the plant. This protocol ensures that every harvest day is efficient because we aren’t having to examine individual blooms for signs of imperfection.

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In the past, when we’ve skipped a harvest or delayed it by a few days, we end up spending twice the amount of time in the patch sorting and grading flowers. What a nightmare! The three day rule has changed everything and now we can comb the patch, almost without looking because every flower is at its prime and in perfect condition.

Erin Floret truck of Dahlias
 
We cut straight into cool water, no preservative and the flowers are quickly shuttled into our 38-40* cooler for at least 12-24hrs. before heading out to customers. This approach gives a solid week of vase life and we’re consistently told by our buyers that our dahlias last longer than any others they’ve tried.

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When I asked our friends Tony and Denise from Bare Mountain Flowers in Oregon what they do for the best vase life they shared, “We harvest early in the day before noon and put all the stems in a solution using Chrysal Gerbera Chlorine tablets. We use 1 tablet per gallon water that has OVB hydrating solution. The flowers are left in the hydrating solution for 2 hours in our cooler and then transferred to a fresh container with one more chlorine tablet per gallon of fresh water. We use no flower food as we are typically moving the flowers to market within 24 hours of harvest. Once in the vase we do recommend use of a basic flower food.”

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Bob Wollam from Wollam Gardens in Virginia also chimed in with his secret recipe,”We cut our Dahlias into hot/warm water in the field and then again into hot water with a Chlorine pill and Chrysal #2 in the packing shed. We then try to hold them for 12 hours in the cooler at 38 degrees before taking to market.”

Erin Benzakein Floret
 

Tuesday we’ll dive into digging, storage and dividing techniques plus my favorite sources for tubers here in the states! If you have sources in Canada the UK, AU or NZ you love, leave their info in the comments below and I’ll happily add them to the list.

57 Comments

  1. Jenn Smith on

    I have grown Dahlias in the same location for 6 years now and the last two years they have really struggled. I start them early and transplant after frost when they are around 12″ tall. This year they stayed small, and bloomed later then normal and didn’t produce a lot of anything. It is really disappointing as it is a dahlia bed with ~40 dahlias in it. There are other perennials and annuals mixed in. This year I did give them one low Nitrogen fertilizer to help but I wondering what else I can do? I plant with bone meal and preventative slug bait. ? Should I not keep planting them in the same location? What is a good crop rotation for them? Wondering if they have depleted the soil of all the goodies they need?

    Reply
  2. Linda Bradley on

    Erin,
    Thanks for the great information. I am wondering about crop rotation. Can I plant my dahlias next year where I have grown zinnias this year?

    Reply
    • Team Floret on

      Hi Linda, that shouldn’t be a problem!

  3. Susan Wright on

    I’m in the Cowichan Valley on Vancouver Island in Canada. This summer I’m growing Dahlias in my veggie garden for the first time for a friend’s wedding.
    I’m on a horse farm so old horse manure, and bone meal were the only additives to rather clay soil. I also mound the beds so I could plant earlier when the ground is soggy. Once the plants were About 1-2 ft high I mulched with about 3 inches of old hay. Every inch of my veggie garden that’s not growing something is mulched repeatedly with old hay. Have very few earwigs and it helps during our very dry summer.
    I’m thrilled with the head high profusely flowering plants. this was way easier than I thought.

    Reply
  4. Jennifer Penney on

    Mistik Acres in Saskatchewan is a fabulous Canadian supplier of dahlia tubers.

    Reply
  5. Heather on

    Do you have any recommendations for improving color in pale dahlias like ottos thrill and cafe au lait? Both of these struggle to achieve that beautiful blush color, despite amended soil and fertilizer.

    Reply
  6. Vj Motu on

    Beautiful and very helpful information. I am trying to grow in Texas, had great blooms first year.

    Reply
  7. Brenna Flynn on

    Is there a reason that you do not use landscape fabric when growing dahlias?

    Reply
  8. Christy Larkin on

    When you say that you fertilize bi-weekly, do you mean every two weeks or twice a week?

    Reply
  9. Pam Hobson on

    I love the idea of planting dinner plate dahlias in the greenhouse and decided to grow some in our unheated hoop house. But I’ve read that the ideal temperature for dahlias is 70-75 and even with the door and window open the temperatures in the hoop house are usually around 80- 90. Is this going to cook them? What temperature is your greenhouse with the dahlias kept? Do you have fans for temperature control? Thank you for the advice.

    Reply
  10. Diane on

    I hear the Cafe au lait is more difficult to work with than peonies for wedding bouquets. Do you think that’s true? If so, do you have any advice for me? I’ve never worked with them before and the bride really likes them.

    Reply
    • Floret on

      Dahlias don’t bloom at the same time as peonies in my garden (peonies bloom in May; dahlias are later in the summer). I design with what is in season, so what I would use would depend on the wedding date and what is blooming at that time. If your wedding is later, you can put peonies in cold storage for weeks after their prime bloom time, which can really stretch out the time in which you can use them.

  11. Pam Hobson on

    Thanks so much for your expertise and beautiful blog! I will be using my own grown flowers for my nephew’s wedding this summer and I am not a business owner but I’m interested in the chlorine tablets you mentioned in this post. I haven’t been able to find a source to purchase and wondering if you know of a source: I found this recipe and wondering if it would work just as well. 1 tablespoon fresh lemon/lime juice + 1 teaspoon sugar + 1/2 teaspoon chlorine bleach + 4 cups water. Thank you. Pam Hobson, Anacortes

    Reply
    • Floret on

      Hi Pam,
      The tablets are available from Chrysal —although they may be in quantities beyond what you’d need for one event. Best of luck with the wedding!

  12. Lorelie on

    Thanks for all your inspiring flower posts Erin! I’m loving reading them and am getting really excited about growing flowers on our rural property when we move there – hopefully next year! Many of the varieties you mention are not available here in Australia but it has helped to give me an idea of what I like in terms of form and colour.

    Thank you!
    Lorelie (Australia)

    Reply
  13. Jen Hanna on

    Does anyone know a dahlia supplier in Australia for the gorgeous ‘Cafe au lait’ variety?
    I would love to try growing them. So beautiful.

    (Are they difficult to grow in a warm Mediterranean climate?)
    Thanks for any tips
    Jen

    Reply
    • Holly on

      I don’t think the Cafe Au Lait variety has been imported into Australia, however the following site
      http://www.nurseriesonline.com.au/countrydahlias/ has a very large range of varieties – non that are much similar to Cafe Au Lait though – but others are gorgeous. I haven’t found anything closer than apricot to coffee coloured dahlias (I live in Melbourne), but live in hope!

  14. Sara Brown on

    Thanks so much for this post. It is my second year for dahlias here in Kentucky. Last year I had no idea how large they would get and I will definitely plant them in the field instead of my raised beds.

    Reply
  15. catherine on

    Hi Erin! Thank you for sharing all this amazing information with prospective flower farmers like myself. You’;ve created such a wonderful resource! Have you tried using neem oil to control insects like aphids & earwigs? it sounds like a great eco friendly option. http://www.neemaus.com.au/product.php?cat=18 This is an australian site, but i’m sure there would be a similar product in the US

    Reply
  16. Angela on

    Erin, You said that you don’t use any preservative for your dahlias, what about for your other cuts? are you buying or making any holding, hydration, antibacterial solutions at all? If so, how broadly do you use them? Thanks!

    Reply
  17. Jay on

    I will begin by saying thank you. Your blog is so beautiful and inspirational! I will then folllow by saying: I know nothing of planting, but have dreamt of having a flower garden and flowers in my home since I was 7. I am now in the process of buying a house with plenty of space to grow a modest flower garden (hurray!) and your blog has already been so informational, even for a total newbie like me. I have a lot of work ahead, but you have unknowingly pushed me in the right direction.

    Now it’s down to learning all about what flowers will grow in zone 4.

    Thank you!

    p.s: your blog just swayed me to believe dahlias are some of the most beautiful flowers ever.

    Reply
  18. Hedgerow Rose on

    Erin–these Flower Focus posts have been such an incredible resource, I can’t thank you enough. Would you ever consider making them available as a PDF so we can print them out? (I’d love to put them in a notebook as an easy reference.)
    ~Laurie

    Reply
    • Lorelie on

      Love this idea! I’d love to print out some of your notes for reference too! My husband and I have purchased 20 acres and I’m keen to try some flowers for my own cut flower use and maaaaybe (a bit pie in the sky at this stage!) one day I can become a flower farmer too.
      Lorelie (Australia)

  19. kim on

    to combat earwigs we put out jar lids or pie pans with water a little soy sauce and a drop or two of soap, suckers love it and drown. empty them often

    Reply
  20. Paula Carli on

    I use diatomaceous earth, the food grade for all my vegetable and flower beds for mites, ants, earwigs, slugs. I am able to purchase a 40 lb bag at my local farm supply place and sprinkle it around all my fruit trees, the premeiter of each flower/vegetable bed; I even put it in my chicken coop. It lasts a long time, only if you put sprinkle water on it, or if it rains hard, would you need to re-apply. Normally within a few days, all insects are gone; then if re-appear a few weeks later, I apply again.

    Reply
  21. Leslie Spang on

    I’m really going to give diatomaceous earth a try for a couple of seasons. Really supposed to take care of a lot of pests ESP earwigs, snails and slugs. Our overnight terrors!!! I am going to be dusted and dangerous! Read u can also mix with sand to act as a spreader for around plants. Gets in the ground for grubs too.

    Reply
  22. Amy on

    Pots stuffed with straw or hay , hung upside down on bamboo canes work well…. need emptying regularly!

    Reply
  23. Margie on

    Erin, Thank you for all your inspiration and support of all of us. Last year we grew about 80 dahlias (about 18 varieties) for the first time. Put them in on the last suggested planting date, flooded 2 weeks after they emerged and we still made money on the delightful girls Over 70 varieties going in this year – all to you showing us to just try and trust in our selves – it just takes time and TLC.

    Reply
  24. Elodie (madame love) on

    Oh my god, this is so beautiful. The Café au lait are definitely my favorite variety.
    Have a great day
    Elodie

    Reply
  25. shinelittlelight on

    oh oh oh and another question! How do you judge when a flower is ready to pick? It looks from the pictures like they are very open when you pick them – is that right? xsx

    Reply
  26. shinelittlelight on

    Hi Erin,
    Thank you so much for this amazing information – I am daydreaming about my imaginary flower farm from my office. Can you tell me how deep you plant your tubers? Also will you cover what you do with them once you are harvested? Digging up, dividing, storing? Thank you so much.
    You are an inspiration!
    Sophie (Australia)

    Reply
  27. Michelle D on

    Thank you, placed my order (ordered some café au laits)…I’ve also been ordering your recommendations, placed my poppy order and sweet peas and now dahlias…waiting on the mums! Hopefuuly you will get something nice from these vendor resources you are giving them lots of business! I am grateful for all the amazing posts you are doing… keeping me going !

    Reply
  28. Katie on

    Thanks so much for all the wonderful information you share! This post was perfectly timed for me, as I will be growing dahlias for the first time for my wedding this September. Thanks from Chicago!

    Reply
  29. Clare on

    Fabulous post Erin! I really like the support system you use and I may try that this year. For pests, I’ve had good results with companion planting – alyssum works well to attract beneficial insects (that will munch on the aphids and earwigs. It blooms al season long so you don’t need to seed it continuously.

    Reply
  30. kelly on

    Totally off the subject…What are your favorite kind of muck boots?

    Reply
  31. Val Schirmer on

    Last year I tried the trick with the plastic irrigation pipe, but the earwigs weren’t tricked! The little shits.

    Reply
  32. Lindsay on

    Thank you Erin for your detailed information. You are a blessing to myself and my husband as we move forward this season with a U-Pick It flower farm in AZ. You have become my guiding light! Thank you for all that you do.

    Reply
  33. Paul Flack on

    What do you think of using straw as a mulch if you don’t have leaves or grass clippings?

    Reply
  34. Jesi on

    w o w

    These are so beautiful!

    It’s absolutely amazing how much you know, and the flowers you grow are the most beautiful I have ever seen! Jesse (my husband) has definitely gotten the message of where to get a bouquet for me for our anniversary ^_^

    Reply
  35. Pinouille on

    Thank you! I only wish California were not in the 3rd year of its worst drought. It has affected my gardening.

    Reply
  36. Michelle on

    Erin, I bought nearly every dahlia that you listed as a favorite. I did the same from your sweet pea list. Basically, I buy everything that you like, ha!

    This season is going to be glorious and I thank you for all your amazingness.

    Reply
  37. Doug on

    Erin, do you disbud any of your dahlias, especially large ones such as the Cafe au Lait? I grew them for the first time last year and got the impression that they would have been even better had I disbudded them.

    Reply
    • Floret on

      No I don’t disbud, too much work. For the big flowered types, we pinch low to encourage branching and smaller stems. This worked great!

  38. Laurie Garza (Fleurie) on

    Thank you for the valuable information! I just purchased about a hundred tubers, so very timely for me.

    Reply
  39. Shanti on

    Do you still start any indoors and take cuttings? I’d love it if you would go over any tips on that method that have worked for you.

    Reply
    • Floret on

      I still do some but have been dividing tubers more and more since we’re maxed on g-house space. This is the best explanation I’ve ever seen and these guys consistently get great results!! http://www.scdahlias.org/200807/howto/cuttings.html If you’re OG then you need to use Elle Pots or soil block instead of the Jiffy plugs.

  40. Robin Lensi on

    I love all your advice and pictures. Keep them coming and thank you!

    Reply
  41. Alexandra Jusino on

    Yeahy you will talk about storage and dividing tubers. This is were I fail every single time.

    Reply
  42. Michelle D on

    Beautiful….takes my breath away…love…I looked at elkhorn several weeks ago and out of café au lait, very disappointing, any other resource for finding them?

    Reply
  43. Heather on

    I found Café au Lait tubers at Botanus out of Langley B.C. I’m so excited to grow them this year! I will have to start mine indoors because of our short season here in Alberta. Do you have any tips for that?

    Reply

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