Starting dahlia seeds

calico20hill

I am excited to see plants growing form Rock Run Ashley seeds I collected last year. I don't think I have tried seedlings from it before. I started quite a few of my seeds recently so the fun of seeing what sprouts has started.

Bessie

Thank you @calico20hill for starting this thread. I look forward to your words of wisdom. I started seed on January 18th that was collected from last year(my first year growing dahlias from tubers). On Friday(March 3rd) I pinched the terminal growth point of 75 plants( 3 plastic bins worth), photographed each one, gave each one a unique number, and took some notes about each one. They've been getting "tough love" outside during the days for over 2 weeks. They stay in their bins whether it's cold, rain or shine. I bring them inside my house during the evenings. It should be just warm enough for them to get planted outside in a week or two. 75% of the seed is from Alloway Candy, with the remainder of seed coming from 3 other varieties. I must learn to wait patiently for seed to ripen before picking the pods. I am so excited to see what kind of flowers I get. Based on what the professionals say, I'll be lucky if only one of the seedlings is good enough to keep for another year. I'm preparing myself mentally to not give up after only one year. My goals are 1) easy to grow healthy plants and 2) good cut flowers(that topic needs it's own thread).
Here's one bin full of seedlings, soaking up some sun after a rainy morning.

SteveM

Bessie Based on what the professionals say, I'll be lucky if only one of the seedlings is good enough to keep for another year.

Those are looking great! I bet you will keep at least 10 of those for a second year. 🙂

PNWGal

Bessie Based on what the professionals say, I'll be lucky if only one of the seedlings is good enough to keep for another year.

Advice from Ted when I first started growing seedlings: don't be too surprised if you don't get anything very good in your first years. AND don't be surprised if you DO get something very good in your first years. Which is to say, don't throw out a good seedling just because you are new at this and think you can't have a good one yet. Sometimes luck does go your way!

Bessie

SteveM thanks! I can use the encouragement. I think that picture is the bin that I put the ones that looked the most "stocky ", and would get top priority for location. By keeping records of what looks really good as a seedling at 6 weeks old, I will see if I can correlate that to the final plant's hardiness and plant structure. What was really exciting was to see a handful of the seedlings throwing lateral branches without any pinching. Call me crazy, for sure, but when pinching the seedlings, I saved the ex-plant material if it was large enough, and made cuttings. That is just an experiment to 1) practice making cuttings 2) determine if a tiny cutting's ability to root will give any insights into the mature plant's characteristics to multiply.

calico20hill

THose are lovely! Where are you at that they do this well outside? Somewhere warmer then we are I am sure! I am certainly no expert at this. I have just gotten the luck of the draw a few times. But I really don't know anything about growing them in other climate zones. I am in 8b in NW Oregon with a coastal climate. Its mid afternoon here and the temperature is 47 degrees at this moment. I Start my seeds in a heated small greenhouse but do not use bottom heat. And I Am one of those independent types that likes to start their seeds in potting mix, not on paper towels. I scatter a bunch of seeds in a 4" pot then transplant the ones that grow to give them more individual space as they need it. So far, that has worled really well for me , and with my poor vision it is probably easier to work with a seedling then a tiny sprouted seed with hair roots.

Bessie

calico20hill I live in zone 9b, about an hour's drive North from San Francisco, 35 minute drive from Bodega Bay. The lows are around 27 degrees F. maybe 7 days a year, with light frost 2-3 weeks of the year. I started the seeds on paper towels, in my oven, with the LED light left on for heat. I kept a thermometer in the oven to make sure the temp didn't get over 86 degrees. I planted up seeds as they sprouted into 3 oz. paper Dixie cups. I grew the seedlings under strong grow lights for 3-4 weeks before potting them up into larger containers. The plastic bins act like mini greenhouses. I started putting the bins outside a few weeks ago, bringing them inside at night where I positioned the bins over and very near heater vents. I think strong lighting and monitoring for the need for fertilizer helps keep the seedlings growing strong. I took the advice of @SteveM in Cubits.org and purchased the Expert fertilizer( sub for Miracle Grow I usually use). I have learned nitrogen is critical for healthy vigorous seedling growth. Phosphorus and potassium are also good, but nitrogen is most important, whether you choose to grow organic or inorganic.

Bessie

Bessie @MissyWeitzel discussing tiny cuttings reminded me that I never gave an update on the tiny tip cuttings I took when pinching my seedlings. I started the cuttings before I had my lights and bottom heat setup, so they didn't get ideal conditions initially.
Here they are early on.

Only 5 survived: 06, 09, 34, 39 and 45. The back left cutting was taken recently from plant 51, and was not a tip cutting. I have little clues on what made these not die. I'll be watching the mature plants to see if they are "special" in any way. Today's photo below. They are ready for the outdoors.

Teddahlia

We sprout the seeds about April 1st with the intention of planting them into the ground on May 10th or so. The ground temperature is the key for planting dahlias into the garden and if the soil is not warm enough, they will not thrive.

Bessie

Teddahlia thank you very much for relaying your growing techniques! I compared the weather in your city with mine. It looks like the Dahlia seedlings shouldn't go into the ground in my area till the beginning of May( daily temps high/low ₇₀/50) . I compare that to the temperature that basil needs, since basil doesn't like any cold. Looks like I'll need to get creative to achieve success. Maybe I'll use something like "hothats" to compensate for the cooler weather. Also, I've found success with watering seedlings in the morning with very warm water when in the ground is still cooler than the plant likes. In any case, to focus on the seedlings, I will not add to my work by waking up tubers too soon.

calico20hill

PNWGal

Absolutely! Remember, Salish Twilight Girl, Salish Snowday , Salish Alpen Glow, S. October Wedding and S. Sailors Warning were all from my first ever seed patch. And I only planted a small area.I must have had some good seedmakers in those first 60 or so seedlings. And even if they aren't quite what you want, if other people love and want them then that is cool too. I am still trying to get Clearview David back as I think it was one of the good seed makers. I see Clearview Debbie on lists but I haven't gotten my hands on David again.

PegMc

I guess the discussion on grow lights must have stopped over @ Cubits as I'm not finding it here. Just wanted to share that I've done a non-scientific (obviously) exercise. I have two 5-shelf shelving units as my set-up. One has white LED lights and this is their second season of usage. The new shelving unit has the full spectrum LED lights (Barrina LED Grow Light 252W(6 X 42W 1400W Equivalent) 4ft T8 Full Spectrum V-Shape With Reflector Combo Linkable Plant Lights For Indoor Plants 6-Pack) that cast a pink light. I'd decided that a combo of both could be the best of both worlds, so for the first several weeks I was shifting trays from one set-up to the other, and back the next day. Very good growth rate. My next step was to NOT shift the trays out. Growth definitely slowed. It seemed that the trays that were on the white LED set-up did better growth-wise than the trays that I'd kept in the full spectrum/pink -- which seemed almost stagnant. At the end of the first week, I went back to switching them out like I'd started, if not every day, definitely every other day. Growth rate picked back up.

calico20hill

THis is very interesting. I am glad I don't have to switch to pink lights :-)

Teddahlia

For rooting cuttings and starting seedlings the full spectrum bulbs are duds. I am glad mine failed after one year as they were terrible. They are designed to add the spectrum of light to get a plant to flower or grow fruit or seeds. All we want are roots and leaves and it is the amount of light rather than the color of the light that counts.

PegMc

I agree. I also hate working around them. It's hard on the eyes.

Bessie

For those of you that have grown dahlia seedlings in the ground, do you have any "words of wisdom" regarding spacing the plants? Based on the height of the seed and pollen parents, and what the seedlings look like at 6 weeks old, I'm guessing most will likely grow to be 5-6' plants. Thanks!

Teddahlia

We have grown about 1,000 seedlings per year (or even more) for a couple of decades. They grow well spaced 6 inches apart all ways. We plant in a double rows (two rows 6 inches apart is one row) and plant about 150 plants in a 50 foot row. The spacing between the double rows can be as little as 3 feet but I consider 4 feet to be minimum. Our rows are spaced 4 feet, 4 feet, 4 feet, 7 feet, 4 feet, 4 feet, 4 feet, 4 feet. The 7 feet is to give you a walkway in the middle of the seedlings. How tall do they get? I would say that a first year seedling in our garden reaches about 90% of it's height , whatever that would be. So a 6 foot seedling might be 6.5 feet tall the next year. Young people rip out the seedlings with poor blooms right after they see the crappy flowers. Old people do not have enough energy to do so and sometimes we cut some off to give the good ones a bit more room. That is not much of an issue actually.

Bessie

Teddahlia thank you!! My garden isn't open land, so I'll have to work around existing hardscape and plantings. Your advice is very helpful to understand how closely I can plant and not create a disaster 😳. Hollyhill genetics will likely get full credit for what looks to be seedlings on steroids. (And so far, they are not over fertilized)

Teddahlia

Margaret will not use paper towels to sprout her special seeds. I will be sprouting lots of my seeds(his and hers seeds ?) on paper towels in a week or so. She does not want go through the agony of extracting sprouted seeds from the fibers of the paper towels. She will use germination mix in small pots and sprout in batches of about 15 seeds. Her seeds need no attention for couple of weeks while paper towel seeds need daily attention for about a week.

Bessie

Teddahlia that's a great plan, for both of you!
I've sprouted on paper towels or baggies for as long as I can remember, for larger, more precious seed. Last year I successfully grew saved single dahlia seed, some years old, along with the Showtime seeds, in rows, in a small container under lights. They separated easily. At your scale, Margaret's plan is more manageable. However, if I had seeds from a special hybrid cross, I'm sure I'd go for the paper towels. I had some seeds this year starting on paper towels laid on top of an Aluminum cookie sheet, covered with saran wrap. I'm going to be really careful using any aluminum in the future. I suspect it might alter the pH , but that's a total guess.
Dressed now in my grubiest, warmest, planting clothes.... today is the day the dahlia babies get planted in their baskets, into the ground. They get the prime spot that last year's tubers had.
I was reading last night on the Yara website on nutritional deficiencies. It reminded me that I actually fortified my soil with Calcium, by putting too old milk and yogurt into the grey water the dahlias got. That likely helped the Donnatella tubers grow nicely.
Good luck with seed sprouting😁

calico20hill

Teddahlia I'm with Margaret on this one. That is exactly how I start mine. It seems like so many times Mother Nature had it figured out and doesn't need our help other then to supply the "ingredients" for successful seed starting. As more seeds germinate in my pot I lift out the bigger ones and repot them maybe 4 to a pot. So much less finicky and I seldom have any that struggle after transplanting.

Krista

Bessie “fortified my soil with Calcium, by putting too old milk and yogurt”
Oh this is interesting! I did not know that the calcium in dairy products is in a form that can be absorbed by our garden plants, very cool this works for you. I’ve admittedly tried the raw milk dilution for combatting powdery mildew, I can’t lie. 😅