Grafted scions drying up before taking

[jmaxton]

So I'm doing OK with grafting various types of cactus seedlings on Pereskiopsis Spathula, but I'm trying to improve my technique and hoping my fellow Nexians can lend some advice. I always have quite a few scions that die off before they take, maybe 5 or 6 out of 10. Some get a pinkish/reddish rot that takes them out. This type of mold/fungus is common in my house and grows everywhere moisture is present. I assume it gets into the grafts due to issues with sanitation, although I always sterilize my utensils with IPA after each cut. The pink rot accounts for about 2 in 10 grafting failures, so while I realize there's room for improvement there I'm not too concerned about it at this point. I'm going to try washing the seedlings with tap water before cutting them next time to hopefully remove the majority of these nasties.

Anyway, of greater concern are the scions that don't rot but never actually attach properly to the grafting stock. These account for about 4 in 10, sometimes more. I live in an extremely dry climate and they seem to curl up around the edges after a few days and just never fuse properly. I'm keeping them in a humidity dome and the vascular cambium alignment seems OK. I honestly think they're just drying up before they can properly fuse. After placing them on the stock I'm always sure to put a little pressure on them to squeeze out any air bubbles, then I just throw them in the humidity dome for about a week. Some do fine and fuse properly after that time and some don't. Should I be keeping them under the dome for longer than a week?

I've noticed that most of the scions that don't take have dried around the edges of their cuts so the once-flat bottom part becomes more semi-spherical. As a result the scions are no longer in good contact with the grafting stock. Does anyone have any pointers on keeping the scion in contact with the stock so that they don't dry out or at least fuse more quickly? I've heard of some people using clear pen caps to weigh the scions down onto the stock, but I'm having trouble finding caps that are wide enough and won't pinch the scion. I had a few little guys get stuck inside the pen cap- very frustrating. I'll keep an eye out for bigger caps though. I've also tried super glue but that seems to make my pereskiopsis very unhappy. Another technique I've seen used for larger grafts is to secure the scion with parafilm or rubber bands, but that seems like it would be very difficult with small seedlings.

Does anyone have any other ideas I can try? Am I missing something obvious here? If anyone with more experience can provide suggestions I would be eternally grateful. I tried to get some pics of a few of my failed grafts but my camera's not really good enough to take clear pics of very small objects.

Anyway, many thanks for reading this long-winded post and contributing any ideas you may have.

Peace,
-JM

 

[dg]

Grafting Book L.W. Grafting Bible - Cultivation - Welcome to the DMT-Nexus

check this out

 

[jmaxton]

Thanks for the link dg, but I've seen that (excellent) tutorial before and I believe I'm doing just about everything Teonanacatl suggests. Is there something I'm missing in there?

Anyway, I'm sure I'll perfect the process with practice. I'll surely be posting more pics of my trials and tribulations as time goes on in case anyone's interested. I'm thinking I just need to keep it more humid and maybe in the dome for longer since my climate is so damned dry. If anyone else has any suggestions, please feel free to fill me in!

Thanks all,
-JM

 

[dg]

im sorry i actually just skimmed your post the first time, shame on me

ok, so your environment sounds pretty good, dome for humidity
some q's

do you use a heating pad? and idea of temps inside the dome?

is it very humid inside dome?-water condensating rapidly?to humid for too long will cause some rot.

are your pere rooted?
if so, how tall/thick are they?

soil medium the pere are in?
how much do you water the pere during graft time?
are they possibly over hydrated, and keeping the scion from sticking?

what kind of light are they under, and how far from the lamp are the scions?

answer those, and i'll see if i have more

 

[jmaxton]

Well don't take my word for it since my two attempts so far both failed but I understand that it is important for both cacti to be in active growth (mine weren't which is why I think they failed). Also I read that awesome PDF dg linked and one thing that occurred to me is if you are leaving any IPA on the blade. The tutorial says he doesn't bother with it but he also says that it should be rinsed off (or I guess you could just wait for it to evap too) because it will damage the cactus tissue. Also I have read that plain old scotch tape is good for securing the scion to the stock.

Thanks for lending your brain to my problem Fiashly. I'm sure I'm missing something simple in my technique, so any ideas are helpful at this point.

The peres and the scions are both undergoing active growth when the grafting is performed. The Peres is always growing since they're in my indoor grow space and the scions are from seedlings that are just a few months old and also live indoors under lights.

I do use IPA to 'sterilize' the blade before each cut, but I'm careful to let it evap before doing any actual cutting. Maybe my eyes aren't able to pick up some residual IPA on the blade, but I'm relatively certain that it's dry when the cuts are made. I'll give it a few more seconds after it looks completely dry next time, just to be sure.

I'll also give the tape idea a try on a few of them next time around, but these guys are pretty small and it can be tough to get them to stay on top of the stock when I'm not playing with them. I've had a few that just fell off from the movement of the humidity dome when I lifted the lid to spray some water inside. To be clear, I don't spray the grafts directly, I just mist the interior walls of the dome to keep humidity up. One thing I noticed in Teo's PDF is that a bowl of H2O is placed inside the dome for extra humidity. I'll do that next time as well.

Again, thanks for helping! I truly appreciate it. I'm sure my success rate will increase with enough practice and when I do I'll be sure to share my experiences here for anyone else who's interested in this fascinating hobby. For now I'm experimenting on my 'less valuable' specimens in hopes of getting it right for some Willies and such.

-JM

 

[jmaxton]

im sorry i actually just skimmed your post the first time, shame on me

No problem. I realize it was a long-winded post, but it took that many words to accurately describe my situation. Thanks for reading over it again.

ok, so your environment sounds pretty good, dome for humidity
some q's

do you use a heating pad? and idea of temps inside the dome?

I don't use a heating pad under the grafting chamber at this point, just on my seedlings and cuttings. Temps in the chamber are 75-78 during the day and 72 or so at night. I have an extra reptile heat mat that I can place underneath the dome, so that will be added on the next go-round. Thanks for that suggestion.

is it very humid inside dome?-water condensating rapidly?to humid for too long will cause some rot.

There's always some moisture on the walls of the dome. Based on my experience with fungus cultures, I'd say about 90%-95% humidity. Condensation droplets are not constantly forming and then running down the insides of the dome like I would expect with 95%-99% humidity. These are all estimates, of course. I don't have a hygrometer accurate enough to really measure it. I've always found those things to be inaccurate so I try to estimate based on visual cues.

are your pere rooted?
if so, how tall/thick are they?

The peres are rooted and actively growing when used for grafting. They root after about 10 days or so in my setup and I always wait at least a few weeks before using them for grafting to be sure they're properly established. I usually let them grow tall enough to produce a 5"-6" cutting, then cut that off and graft on the bottom half, which is also about 5"-6" tall. I just broke out the tape measure and they're about 1/4"-3/8" thick, mostly closer to 1/4". That's about as large as mine get. Is that about average? Based on the pics I've seen online they look to be pretty normal.

soil medium the pere are in?

I use nursery-purchased cactus soil for my peres. It's got a higher ratio of organic matter than what I now use for seedlings which seems to be OK for them. They root quickly and take off, never rotting or showing signs of damping off.

how much do you water the pere during graft time?
are they possibly over hydrated, and keeping the scion from sticking?

I don't water them for about a week after grafting, but I normally give them a decent watering anywhere from a week to a couple of days beforehand. I've been trying to find the sweet spot there, but I've never had a scion forced off because of too much juice being pushed up out of the stock. If anything, I'm probably letting them dry out too much because I don't always get enough 'sap' on top of the peres for the scion to adhere really well.

what kind of light are they under, and how far from the lamp are the scions?

The grafting area is under a small spiral-type CFL, probably 1.5' away from the scions. It produces just enough light to keep them going. I'm not 100% sure of the wattage, but it's not very strong. My first few attempts were done in my main growing area and a lot of the scions turned red pretty quickly so I moved them out to another more dimly lit area where they maintain a healthier looking green color. Some kinds still turn reddish after being cut, but I think that's a stress reaction. They normally green up again after a few days. I keep some peres in this area too because of space issues and they grow, but not very quickly. It seems like enough light for moderate growth, but not very intense.

answer those, and i'll see if i have more

Thanks again for spending the time to help me out dg. Your questions are helping me to really analyze my situation and rethink a few of my ideas. I truly appreciate your contributions to this subforum and the Nexus in general. Thank you!

-JM

 

[dg]

Jmax-i like having good people to share my passions with, so its my pleasure


sounds like a good set up.
i always used tube floros-40w shop type, kept the new scions 4-6" away max...but i dont think its an issue in your set-up

you say the seedlings are months old before grafting?--thats prolly the problem they should be grafted 7-14 days after germ, while they still have seedling vigour

give your set-up a try with fresh week-old seedlings i bet your sucsess rates go way up

 

[jmaxton]

you say the seedlings are months old before grafting?--thats prolly the problem they should be grafted 7-14 days after germ, while they still have seedling vigour

give your set-up a try with fresh week-old seedlings i bet your sucsess rates go way up

Ah, that's a good idea. In my experiments so far the seedlings have noticeably slowed their growth by the time I graft them, so lack of vigor could definitely be a problem. They just look so tiny and vulnerable after a week or two- I almost feel bad cutting the little babies in half! But it's for their own good, so I guess I can force myself.

I have a bunch of seeds I plan to germ this week, so I'll check back in with the results of my next batch before long. Thanks, yet again!

-JM

 

[dg]

ya, gotta get them when actively growing for best results
let us know how the next batch goes