Dahlia Bed Prep- Raised Beds

This is a post I probably should have written years ago based on the number of questions I get about how to fill a raised bed. I’m speaking to this topic from the viewpoint of dahlias but it can be used for general gardening purposes as well.

Raised beds are excellent places to grow, especially if you live in the land of clay soils like I do. Years ago when we moved on to our farm, I saw a sloping hillside and instantly knew that raised beds were my answer.

So let’s talk about the benefits of raised beds:
1. Erosion control- this was huge for our farm because everything is on a hill. The only flat land is our front yard. You don’t necessarily have to have permanent sided raised beds for erosion control- this was the route we choose but even mounded rows will work.
2. Drainage- We know dahlias need good drainage. They don’t like sitting in water. You don’t have to go super high on your raised beds either, especially if you have a bit of a slope. With a slope, 6 inches is about the minimum for how much you want to be mounding your dirt or the depth of your raised bed. On flat ground, go 8-10” if you can. Deeper is always nice but not totally necessary. However, sometimes deeper means a higher bed so you are supporting your back more- totally on board with that the older I get!
3. Timing- Raised beds warm up faster allowing you to plant a bit earlier and also allowing you to plant after heavy rains. We got several days/inches of rain recently. The morning after the storms, I checked the raised beds in the field and the moisture level was perfect for planting tubers! I’ve never had to wait after heavy rains to plant because of my raised beds.
4. Labor saving in the long run- Raised beds are more prep work financially and timewise in the beginning but save so much time over the years because you don’t have to re-till and reshape every season. They are also easier to keep up with weeding because you are usually filling with fresh weed free soil. So if you keep on top of it from the beginning, you won’t spend hours weeding.

Have I convinced you yet? Nothing wrong with in ground growing but I gotta’ admit I love a good raised bed!

Deeper Raised Bed (that needs a little repair work!)

So what are we going to put in that raised bed?

I’ve started raised beds 2 ways and they both work great- one is just a little more work.
Method 1: Mow your grass very short— scalp it. Then cover the area with cardboard and construct your raised bed on top of it. The cardboard will kill the grass overtime and break down. This is the method I use in my vegetable garden.
Method 2: Till the area and get all the grass/weeds out and then construct your raised bed on top. This is the method we used in our flower field. (It would have taken a lot of cardboard.)

After you get your grass killed or area tilled, it’s time to fill it up. I start with a layer of branches- not big ones, nothing bigger than 2” in diameter. Trust me on this one— 2 years ago my husband designed an amazing raised bed for our vegetable garden, he built it and then began filling it with branches— and logs! He knew that branches were what I used in the bottom but I didn’t realize he had put logs in there until the dirt was already on top!! So needless to say, it’s still breaking down. I’ve been growing plants from the cucurbit family in that bed because they don’t mind a compost like environment. It will be beautiful soil - one day!

Once your branches are down, I add leaves if the time of year is right. Leaves are an amazing soil additive. If you can get them shredded- even better. If they are shredded, you can add a lot. If they are freshly raked, don’t put so many that they mat up when wet.

It’s finally time for the soil! You want a good quality compost. Now what is that and how do you find it? #1- Ask gardeners in your area. Compost is going to be different regionally. #2- if you have time, buy a small amount and get a soil test done before committing to a large amount. I always recommend getting a soil test done on your base soil regardless but if you can get it done before you buy- even better. Some companies may even be able to provide you with a recent test done on their soil.

You don’t have to use 100% compost. You can mix it with some top soil if you can find good quality top soil. All compost gets very expensive. This is where a lot of the financial investment comes into play with raised beds.

Compost can come delivered in bulk or you can buy it in bags. Bags are usually a bit more money wise but they are also faster because you don’t have to shovel and wheelbarrow the soil across your yard. When we set up our flower field originally, we used bags because of the geographical topography of our farm. We didn’t have a tractor with a bucket at the time, so I figured that moving bags was less labor than having to shovel and push a wheelbarrow several hundred feet to the field (and down a very steep hill). I just bought a pallet worth of bagged compost at a time. I tell you this because some people have a misconception that buying bagged compost is crazy but if I can do a 1/2 acre field this way- it’ll work for your backyard garden!

My husband’s raised bed design that is far superior to mine! I love the rocks on the bottom.

If you have bought in good quality soil, then hopefully your soil is well balanced nutrient wise. If so and you are planting dahlias, then I would add a granular fertilizer - something like a 10-10-10 or something with a touch higher nitrogen than phosphorus and potassium to start.
(For more dahlia fertilization recommendations, go here).

That’s my method for filling up a raised bed— What’s yours? I always love to hear new tips and tricks!

The Itsy Bitsy Spider....Mite that is!

Edit: I originally started writing this last fall but didn’t have time to finish the research so I’ve left parts of the original article in but have now been able to do more research to address this issue and have finished the post.

If I had a fiver for every email/question I’ve gotten about spider mites (and broad mites and cyclamen mites) this summer- well let’s just say I’d have lots of cash for some pricy unicorn tubers this winter ;)

It’s been a really rough year for them. Most years, I see small localized outbreaks of them but usually the damage is minimal and easily contained. But this year, it’s been at the ‘fatal damage to plants level’ for some of you.

So while, it’s not a sexy topic, it’s a necessary one if we want luscious blooms!

Let’s talk about how to address pest issues in general first:
1. Scout your plants regularly. Grab your favorite beverage and walk your plants on at least a weekly basis, more if you have a lot of plants.
2. Use your phone camera to take pics of anything that looks suspicious.
3. Record your findings- date, what you found, add a pic if you can. This information is helpful when it comes to prevention methods in future years.
4. Employ prevention methods. But - fully realizing that sometimes it takes a few years to figure out the timing so give yourself a bit of grace.

Most of the time when I receive an email, the plant is already very damaged. Try using these methods to catch issues before they get really bad.

Next: Make sure you diagnose the problem correctly.
— Also remember you can have more than one issue at a time.
Knowing the lifecycle of pests is important. Some insecticides will only kill the pest at a certain stage. You can find the average lifecycle of most pests by simply searching online. Remember that unless you know the timing of when the pests begins to appear in your garden, there will most likely be all stages of the pest happening at once. This often means the need for multiple applications of an insecticide.
— Also verify your diagnosis in multiple places. There are a lot of ID apps and good research out there to use but a lot of these are based on AI which can be faulty so just use good common sense and verify it in a few places.

Research Findings:
*I’m not going to re-invent the wheel and re-write everything I read but I’ll summarize to give you an idea if the research may fit your situation.
Coping With Spider Mites- from The American Dahlia Society. This article talks a lot about different types of mites and specific insecticides to address them. It’s almost 20 years old, would love to see an update but I think there’s still some really good info here. I found the information about the use of pyrethrin’s and how they can actually encourage the spread of mites particularly interesting.
Dahlia: Plant Health Problems- This page is not specific to mites but to pests in general that bother dahlias (also fungal diseases). Some good photos for id help (wish there were more though).
Managing Spider Mites in the Garden and at Home- This article speaks generally of spider mites but they used dahlias as their example plant throughout. Good photos for diagnosis
Know Your Mites- Good article on the differences between broad mites and spider mites
Management of Broad Mite & Cyclamen Mite in Production Nurseries- long but good photos and in depth descriptions of different types of mites

Experience Based Findings: (For Prevention)
Several years ago I began using a sprinkler to cool my dahlias during the hottest days of summer. Turns out that it’s also a great method for preventing powdery mildew and spider mites. Both of those come on when we go hot and dry. But by increasing the amount of water my plants are getting, bringing the temperature down and keeping the air moisture levels higher, it’s creating an atmosphere around my plants that is not conducive to spider mites/powdery mildew.
Second - Keep your plants as healthy as possible. This means staying on top of feeding and watering and monitoring for pests. Stressed plants attract more bugs!

I sincerely hope this year is better- but when they do inevitably come, there’s a lot of good information here to help answer questions and help you formulate a plan of attack.

Growing Dahlias in High Heat

You love dahlias but you live in the land of scorching sun! What to do? Well- here’s a blog full of tips for growing with more success in high heat.

I’ve written a lot on this topic with tips on different methods for success in high heat but I’ve never compiled it into one place. Some of this will be links to past blogs (no sense in re-writing it all here) and some will be newer methods we have learned over the years. So here goes:

1. Variety is important. Some varieties just don’t work super well. I wrote about how I choose varieties in part 4 of the Dahlia Game Plan series last winter. I also have a whole module about choosing varieties in my Dahlia Growing for Beginners Virtual Workshop.

2. Watering is crucial. Several years ago I started experimenting with pulse watering. It was a game changer for keeping dahlias hydrated in high heat! I wouldn’t go back to my old method now. Read more on that here

3. Shade- Shade cloth or location- either one works. So we grow 1000’s - it’s not practical for us to use shade cloth. Would it help - Sure! But our fields are multiple places and too big to do it cost effectively. This is why I’ve worked on other methods (as listed in this blog) to give us success growing in high heat. But for smaller growing situations, shade can be a powerful too.

4. Planting time- This is really important. You need to get plants established before your climate and soil get too warm. Tubers can cook if planted in soil that’s too hot. This timing will depend on your climate. For us, it means get them done by end of May. If you have to plant in warmer soil, try a rooted cutting that’s been potted up. Those roots will establish faster and you can water it which cools your soil.

5. Surround (Kaolin Clay) - We use this as a crop protectant— helps keep early season powdery mildew at bay, keeps mites and thrip pressure lower but also cools the plants several degrees. Longer form blog on it here.

6. Pruning- Dahlias respond very well to pruning. Cutting plant back by half is a great method to employ mid summer during the really hot part. This lowers the stress level on your plants. Usually early July is our timing if we choose to cut back. This method works well if you overwinter your dahlias and don’t have control over when they sprout. You’ll get blooms again 6-8 weeks after pruning.

7. Patience- growing a plant in an enviroment that is less than desirable for it is going to take time to learn. Dahlias can thrive in a lot of places but high heat is a bit of a learning curve. So expect that it will take several years to learn how to do it successfully.

However, I hope these tips will help! Do you have any great high heat growing tips? Send them my way!

Planting Rooted Cuttings

Rooted Dahlia Cuttings are a bit different from a tuber. You are planting an actual green plant with roots instead of an ugly brown root! They both produce gorgeous flowers - they just begin differently.

Rooted cuttings are small when they first arrive. Usually only a few inches tall. Different varieties grow at different rates. You can have little top growth but a full root system. You could plant directly if you are past you’re last frost date but your chances of success get much higher if you pot the cutting up first. Grab some good potting soil and 3-4” pot. If your cutting comes in a pre-fabricated plug like a root riot or the paper contained elle pots- tease as much of that off as you can. On the elle pots, you can just cut the paper and leave it on there. You just want the roots to have freer access to move and expand. If they get restricted, this will inhibit tuber growth and causes the “mass of roots” effects instead of tubers.
Place the potted cutting into a shady/part sun place. Remember that most rooted cuttings have come out of a grow room or greenhouse before shipping and need to be hardened off first. So shady/part sun for a few days and then full sun until the roots fill the pot.
I recommend using a light fertilizer after your cuttings have been potted up for about 10 days or so. I’ve found that they use up the “goodness” that is contained in the pod or dirt they were rooted in very quickly.
Water when almost dry. It’s very easy to rot out a cutting so run it on the dry side but don’t let it completely dry out.

Well filled out pot, ready for planting

After the roots have filled the pot so that the dirt stays together when you pull it out of the pot, you are ready to plant (usually 3-4 weeks). Plant into your prepared garden bed, landscape or large pot (7 gal minimum). Remove the bottom set of leaves and plant so that the node from those leaves is underground. This will help encourage tuber growth.

Water well after planting and pay close attention to moisture levels for the next 2 weeks as it is getting established. Be careful about planting tubers and rooted cuttings near each other because of their different water needs. You can plant tubers a few weeks before your rooted cuttings (say when you pot up your rooted cuttings) and they will be at the same stage by the time your rooted cutting is ready to plant. Therefore requiring the same amount of water.

I get asked a lot about how to get good tuber growth off rooted cuttings. I’ve noticed 2 things:
1. You need to fertilize them as much as tuber grown plants. When I hear of cuttings that didn’t grow tubers, I usually begin digging into the grower’s fertilization plan (and often they don’t have one) or they didn’t fertilize enough. Tuber grown plants won’t make any or many tubers either if you don’t fertilize them. Plants need food to do their thing!
2. Not getting any tubers can also be problematic on newer bred varieties. I’m speaking from observation over a few years here. I’ve tried newer (unicorn) varieties from very reputable breeders who are not in my climate and had very poor results at first. I got the “ball of roots”. I managed to save the root balls- you can put them in a pot with dirt or store in vermiculite. You need to be sure they don’t dry out so humidity is important!! Then I made cuttings off the root balls- so year 2 I got a few tubers- small and not many but some. Replanted those tubers in year 3, got much better tubers. Year four I replanted tubers and rooted cuttings off the year 3 tubers and got good results. So my observation is that new varieties bred in different climates are going to need time to adapt.
So why doesn’t this happen with any variety that is bred in a different climate? It does to a degree. Those of us growing in hot climates know that certain varieties do better here. But also because some varieties have been around so long that their stock has literally been all over the country and mixed around so much that it acclimated.
This is purely observation, I don’t think anyone has done a scientific test on this. But over so many years of growing, I’ve noticed that varieties do adapt to where they are grown.

Let’s Get Planting!

Well, we planted our first dahlias of the season yesterday. We put in rooted cuttings of 20th Ave Memory; she’s a sweet light pink ball.

For some of you, you planted a month ago, for my farm it’s the earliest we can start and for colder regions, you are just waking up your tubers.

But regardless of when you do it, there are always lots of questions about planting. And first thing I want to say about it- Don’t Overthink It!

It’s a really simple process but people tend to overthink it.

Here’s the basic process for planting a tuber:
1. Dig a hole 4-6” deep. Deeper if you have really good draining soil.
2. Put the tuber in (lay it horizontally if you don’t know which end the eye is on).
3. Cover it with about 2” of soil, more if you have well draining soil.
4. Do you water it? Well if you are lucky enough to live in an area with consistent rain, then no. But if you live in the land of roller coaster weather like I do- you need to look at the weather report. If I see we have significant chances of rain in 2-5 days and the temps are under 80 degrees, then I don’t water. But if it’s hot and dry, then I water once- a good soaking. But that’s usually all that’s needed to get the tuber going.

Here’s the basic process for planting a rooted cutting:
1. Dig a hole ( as big around as your pot is but a few inches deeper)
2. Place your rooted cutting (that has been potted up) and place it deep enough so that you are covering 1-2 nodes on the stem with soil (remove any leaves attached to these nodes). Planting those nodes under the soil gives you more chances to tubers being made at those nodes. But you have to pot up your rooted cutting in order to get a tall enough plant to do this.
3. Water your plant deeply. Keep it well watered for the first 2 weeks while it establishes. Not sopping wet, ensure good drainage but don’t water starve it at this stage.

So those are the very basics but let me cover a few things I get questions about:
1. Planting in no dig beds or raised beds- How deep should they be? If they don’t have a bottom on the bed, then 6-8” is fine, more is okay too. If the bed has a bottom (but make sure it still has drain holes, then 810-12” is going to be better.
2. How do I plant a clump? Same way as a tuber but dig a bigger hole and make sure the old stalk is facing up ( you usually have an old stalk on these types of clumps)
3. When can I plant? After you last frost date (Google it) and when your soil has had time to warm up. If you have warm weather after your last frost date for a week or two, that should be sufficient.
4. Can I plant my dahlia in a pot? Yes, but make sure it’s at least a 7 gallon size. Plant just like you would in the ground.

Got a Planting Question, drop me a line here.