flying dragon seedling death

[brian]

I planted twenty or so FD seedlings last year and again this year.  It seems that ~30% die off right after sprouting, and otherwise healthy seedlings randomly decline or die until only a small number remain.  The four that survived from last year are very healthy and green.  It looks like this year will be the same.

All were treated identically.  They're planted in the same cedar/peat/perlite mix as my larger trees and seem to have good drainage - there are holes in the bottom of the cups.  They get the same amount of water, sun, etc and shouldn't have ever dried out. 

Is this like damping off of tomcato/pepper seedlings?   Anything I can do to improve survival?  I really don't need many I was just growing them to eventually graft other varieties onto. 

These are last years survivors


And this years bunch.  A dozen already died over the past few months and there's more dead ones here.

[Millet]

Brian, most citrus nurseries purchase their rootstock seed from large companies that maintain  groves of trees for the various types of rootstock seed that they market.  Following is the procedure that is commercially used by major companies that market Poncirus Trifoliate seed. You can adapt  from this.  The process of producing large volumes of rootstock seed includes harvesting the fruit at normal maturity, crushing the fruit in water, stirring the resulting mixture with pectinase enzymes at specified temperatures to separate the seed from the pulp, and washing out the seed.  The washed seed has its surface sterilized with 125-F water for 10 minutes, then dipped into a 1 percent solution of 8-hydroxyquinoline sulfate (8HQS), then left to air dry on screens in the shade, and packaged in plastic bags.  When storing, it is important to leave these storage bags open initially until the seed equilibrate with the refrigeration temperature.  If the bags were closed before refrigeration, the undissipated heat and humidity may generate condensation inside the bags which promotes fungal pathogens.  Fresh used citrus seed has the highest germination percentage, however seed can be stored at 40-F for as long as 6 months with little loss of viability.  Seed stored at room temperature looses viability quickly.    NOTE: 8-HQS is just a common bactericide,  if you can't locate it, there are a lot of bactericides that can be used. Be sure that the medium that you plant the seed in, and the seed tray used are completely sterile .  Nurseries that purchase the seed and grow them out add dolomitic limestone to the seedling medium to maintain a pH of 6 to 7, plus controlled slow release fertilizers with micronutrients.  The seed is planted 1/2 inch deep.   Humidity maintained between 80 and 90%, temperatures are kept at 85-F.  Germination is further enhanced by pealing away the testa (outer seed coat).  Germination is further enhanced if the seed trays can be heated from the bottom to maintain the 85-F temperature in the media. Following the above procedures seedlings 2 inches tall with three leaves can be achieved within 10 to 14 days after planting, though it can take as long as 40 days for all the seed to germinate. - Millet

[brian]

Thanks, Millet.  I wasn't sure if this was an issue with citrus seedlings in general having low early survival or something I can control for.  Last year I was using mail order seed. This year I ordered two whole FD fruit.  Both were planted immediately into propagation trays into sterile seed-starting soil.  I re-use these trays, washing them with bleach-water first.  I plant a few seeds into each cell and put them on a heating pad, and cull all but the tallest after a few weeks.  Fairly soon I move them into larger pots but these I do not sterilize and they have been re-used many times.  A clear source of contamination but I was hoping the seedlings would be strong enough at this point to survive the more hostile environment.  I guess I'm too optimistic based on the abuse that larger trees can handle.

[swimmingfree]

i put about 30 FD seeds in one pot of potting mix for house plants got about 20 to grow ... have pull out the two i need if you wood like the other i have let me no .... i live in Michigan so i think im safe to send out....    but i have one question is it safe to send then bear root?
swimmingfree 

[Millet]

Brian, I don't know if it is just the photo but are your seedlings getting enough nutrition?  Many of them look rather yellow, as compared to the dark green seedling growing in the bottom right corner of the tray. - Millet

[brian]

swimmingfree, thank you for the offer but I think I will be okay with the number of survivors for now.  This is more of an experiment, but I'd like to know I can reliably grow rootstock in the future when my grafting skills improve.

Millet, I put osmocote plus in the small containers so they should have necessary nutrients.  The yellowing seems to be rather rapid, these were mostly green a week ago.  It looks like poor drainage or overheating but when I check after heavy rains they aren't damp at the bottom and I think I've been consistent with my watering.  I have also had poor outcomes with tomato and pepper seedlings once potted up.  I wonder if the 4:4:1-ratio mix peat/cedar/perlite might be inappropriate for seedlings?  Or just too many soil pathogens?

[swimmingfree]

brian just trying to help my self out got to many plants right now and winter is coming soon ... the price would be right 
swimmingfree