3,226 Garden Web Discussions | Dahlias
The numbering system for inorganic fertilizer has confused people for years. There are three numbers and they represent the amounts(as a percentage) of the three major ingredients of fertilizer: Nitrogen, Phosphorus and Potassium. "Balanced" fertilizer would have the same number for each element 20-20-20 or 10-10-10. Dahlias like a fertilizer with 5-10-10 or 10-20-20 or even 12-24-24. All this means is that it has half the nitrogen as the other two elements. Most gardens stores sell 5-10-10. Farmers buy 10-20-20 at the farm store because it is twice as concentrated and much cheaper than 5-10-10.
Most of us are going organic. Alfalfa used as mulch is a great fertilizer. Mint compost is also excellent. Both have all three of the three major elements and work quite well. Bat guano and blood meal are good fertilizers. Of course all types of aged manures are the classic fertilizers for organic gardeners. Chicken manure works great but needs to be applied in the Fall as it is too "hot" (too much nitrogen all at once) for dahlias. They say that rabbit manure can be used fresh and needs no aging.
I follow Swan Islands advice. Work lots of composted manure into the soil, put in a small handful of bone meal when planting. Thats usually it. Sometimes I'll hit them with an additional fert in September when they are in manic bloom stages, but not always. I get plenty of flowers without pumping them full of MG.
I disagree with the need to dig them up -- what would that do but set them back.
Frost isn't a big deal at all - if the top dies off, more will grow. In essence, it is the equivalent of a hard pinch or cutback at this time.
When I worked at the garden center, the first crop of Dutch dahlias would be cut completely back when too big and floppy, and would regrow and be ready to put out for sale in about 4 weeks.
Personally, I think cutting back or pinching helps them to be a little less tall and floppy. Depends on the kind, of course, some of the tall dinnerplate types won't throw many side shoots no matter what you do.
Cuttings from Corralitos are done in Oasis foam. They are an excellent product and are easy to grow if you follow their instructions and do not over water the plants. The Oasis foam holds an incredible amount of water and if over watered the roots of the plants rot where the foam wraps around them. If the roots rot, the plants die.
When you receive the cuttings in the mail, let them recover under lights or in the green house for a few days and then re-pot into a larger pot and at that time remove most of the Oasis foam. Your success rate will improve dramatically.
Thanks for the input folks. I couldn't upload a picture but the dahlias seem to have recovered for the most part after drying out, though one or two still have curled leaves.
They didn't include removing the foam in the planting instructions so I didn't. After four weeks my guess would be that trying to remove the foam now would be disastrous for the roots. Well, maybe next year.
Thanks again.
I did see couple of eyes and kept tubers out of the plastic bag for a day. Next day the eyes were dried up!!
However, I still put tubers in the soil. Is there any hope now? This was a week ago and temps were in mid to low 70's during day time and quite humid.
Appreciate you response and feedback.
Anna
I live in the PNW too. I've been crossing my fingers that the week of May 14 will be a good planting weekend. I know that Puget Sound Dahlia Association plans to plant the Volunteer Park garden that weekend and I was planning to participate. I've been checking the 10 day weather report every evening. There is a warming trend, but it's coming on very slowly. I'm considering taking my car out of the garage just to make room for more pots! I have any nuber of tubers that are raring to go.
Phyllis
Rebar makes good stakes and at Home Depot they will cut it to length. Also,. steel t-posts are great, 6 foot ones are about right. I believe that if you have room, dahlias do best tied to stakes. Four dahlias planted around each stake and the stakes need to be 5 to 6 feet apart. This is the way they did it in the 1920s and later. They get lots of sun and you can walk all around the plants. Most commercial growers have gone to planting in rows. It just does not look as good.
I go with re-bar. 5 ft lengths driven home well. I only plant one tuber per stake but a friend grows two per stake. I tried the upside down tomato cages but seemed to get in the way when working around each plant. I paint mine a dark green rustoleum. May try the gray PVC. Sounds interesting and would certainly be lighter than rebar. Steve in Baltimore County.
I've had dahlias, glads, acidanthera, and other "tender" bulbs overwinter here in the Detroit area in the same manner. Deep mulching, deep planting, and well drained soil all help. Of course, its a gamble, but it can work.
The one that really flabergasted me was the year that I had a whole bunch of undug tuberous begonias return. It was the winter of 1997-1998, and we had just a phenominally warm and mild winter due to a strong El Nino -- hardly even any snow that winter. I had probably 50 tuberous begonias in a bed, and never got around to digging them. I just wrote them off -- how could a tropical plant from the Amazon rain forest survive the winter in Michigan, even that mild of a winter -- after all, any freezing at all, or even just cold wet conditions, would do them in. Or so I thought. The entire lot of them, to the last bulb, came back in the spring as soon as it warmed up, and they actually did really well that second summer. I did dig them the next year, and of course lost a fair number of them in my basement that winter!
"Dahlias like vegetable fertilizer, which is typically low in nitrogen (the first number on the fertilizer package.) Use 5-10-10, 10-20-20, or the best would be 0-20-20."
Dahlias need more nitrogen than this. There are posts on this forum about the "low nitrogen myth" Nitrogen washes out of soil and needs to be replenished every year. At the Bonneyville Dahlia trial garden sponsored by the American Dahlia Society they only use nitrogen as the fertilizer because their soil tests say that they have adequate pohosphorus and potassium in the soil. Without doing a soil test, most people should use something like the 5-10-10 or 10-20-20 but do so in moderation and do so several times in smaller amounts until about August 1st. Many people who have used fertilizer in their flower beds for several years will have a build up of phosphorus and should use fertilizer with low phosphorus. By the way, the new "greener" fertilizers are lower in phosphorus.
Russ, Do you actually find taking cuttings like this is simpler than dividing and storing tubers? It sounds like a lot more time and work and babying of the little seedling. Maybe your instructions are just so detailed that it sounds like a lot. I haven't tried it, so I dont know. However as someone who only started growing Dahlias 4 years ago, I have had great success with dividing tubers in the fall and storing them with the sulphur and saran wrap method.
I dont mean to challenge what you are saying - I am just curious as to why you think this method of propagation will be easier for beginners.
Depending on the type of dahlia you have, they do grow large. The saucer type grow as high as wide so with lots of foliage it needs space and needs to be tied up.
That should be arranged far in advance of their growing.
I intertwine them with cord, each supporting each other but stakes at picked places.
Yeah� this is a problem for me as well.
I have a cutting garden and I also put the dahlias all over my other gardens.
Yes, you can see the stakes, but it really only bothers me. I know they are there so I just stare at them�. Other�s cant even see them.
I use regular bamboo stakes. So they aren�t too big of an eye sore. You can also keep them pinched back pretty good so they are bushier and don�t need as much staking.
All in all, I think looking at a little stake is worth it!
Keriann~
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dahlias.net
Sun Apr 24 20:33:24 2011
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They had eyes on them, however, I let them outside one night and the eye dried up. As suggested by one of the members here, I still went ahead and put them in the soil. Till now there is no sign of any growth.
Anna
I had one where the eyes took 3 weeks to start enough growth that I could see it with a magnifying glass. Now that it's potted, it will probably be a couple more weeks before I see anything above the soil.