Situation:
10' x 10" greenhouse in San Diego - Have been harvesting alocasia & colocasia babies - Problem, many are turning yellow and wilting/crumbling away.
help please???
michaelg
(still trying to come up with the best way to keep the GH cooler through the summer - evaporative cooler/swamp cooler?) It's too small to have misters come on through the day to cool it off...
many times when you pull baby plants that small off the mother and replant them they will die back. Give them time, I don't think they are DYING just dying BACK...they will shed those existing leaves and after they are well rooted will put out new growth
I would check for spider mites first they would be under the leaves or on top and look like white dust. They will suck the sap right out of the leaves and cause this type of damage. The next maybe to much heat how hot is your greenhouse getting during the sunny winter days? If it is newly planted it could be shock as well. These seem to be the most common reasons.
Thanks for the info... Couldn't find any pests located on any of the plants. Seems like even the older plants are doing the same thing.
The temps have been reaching over 80 in the greenhouse.
I do need to add better vents/exhaust fan to the GH.
Could it be not watering enough?
Michael-
What's the low temp?
With temps reaching 80F, you may be stressing the plants - too much warmth during the day promoting growth but too little warmth at night with reduced light levels.
Also a problem might be overwatering. Colocasia do love moist soil but only if they are in their accelerated growth phase. Otherwise, you need to cut back so you don't get rot. Alos even like slightly drier conditions.
My suggestion. Make sure the highs and lows are within 20 degrees of each other, e.g., 80/60 or 70/50. Also try to provide supplemental light, to bring the total time up to 12 hours if the temps are reaching 80.
Keep an eye out for spider mites. I find them by running my fingers along the leaves. If you have them, the leaves will feel gritty. PS Don't use insecticidal soap on Colocasia leaves; it will burn them. Just use water. You can use the soap on the stem.
Let us know how it goes.
Rox
The temp ranges have been fluctuating a lot. I do have a portable heater 600 - 900 - 1500 watt settings - ranges about 50-55 coldest, then it could get up to 85 in GH.
Bought a 16" exhaust fan today from Dixiline - $39.95 (with temp control) though it didnt come with a front grill, thought it was included.
My GH has been an adventure so far, never thought that so much of my day would consist of sitting in a 10 x 10 converted shed.
My next big task is to set up a better watering system - am hoping I can do this without having to manually water everyday without flooding all of the plants.
What kind of soil are you using? It may have to high a PH?
I have the same problem as the original poster concerning E.E's but mine are houseplant's and not grown in a greenhouse . My problem is Spider mite's!
What is the best remedy to use! I do not want this problem to spread over the house to my other plant's.
Thank's
Rachel
This message was edited Feb 5, 2009 10:18 PM
Rachel-
Do you have colocasias or alocasias?
In my experience using insecticidal (Safer) soap works well if you follow up every few days for a week.
BUT colocasia leaves can be really damaged by the spray, so I only use it on the stems and use water with a little delicate finger rubbing on the leaves.
My alocasias seem to be OK with the soap on the leaves or stem. But honestly spider mites are kind of rare for me on alocasia.
ROX
Only one is an Alocasia (Hilo Beauty) the rest are Colocasia's. I had read what you wrote concerning the insecticidal soap's on the colocasia's leave's and have been leary about using it. I used a home remedy on the leave's and stem's of just water, rubbing alcohol and dawn dishwashing liquid after I realized what was going on with these plant's. So far it has knocked them all back but I will keep doctoring them every few day's or so for a while.
I have never had a problem with these little creature's before on any plant until now and the only thing I have done different with these vs. any other plant is..I added grow light's for them a little over a month ago. Maybe the added extra light/heat and low humidity attracted the little devil's to them?
Thank's much Rox.
Rachel
Spider mites definitely do like low humidity and high temp.
Spider mite populations can explode under conditions of high temperature (above 85° F.) and low relative humidity (below 60% RH).
Spider mite Life Cycle
@ Temperature in oF: 60, 64, 70, 90
# of Days (Egg to Adult): 30, 21, 14.5, 3.5
http://www.hydro-gardens.com/spidermite.htm
I just dealt with a breakout of mites and aphids on my indoor ee's and oxalis. I put DE on the ground of the pots and sprayed leaves and stems with 90% rubbing alcohol. If you use alcohol, you need to be very, very careful as this is highly flammable. I only use a little bit and directly target infected areas. I would not have this around in a spray bottle if I had kids and do not recommend using in the house. The DE helps to keep the mites/aphids from spreading and the alcohol kills them. For larger plants that are easily handled, Rachel's swabbing is better (I do this too) but it's hard to get all of the critters with swabbing, so I follow up with spray. I have found that insecticidal soap does harm the leaves of some of my ee's and some oxalis.
In the security field, they call it a layered approach. Use multiple alternating methods as no single method will completely solve the problem. You get most of the bugs with swabbing, get some more as they try to spread with the DE, and get some more with the spraying that gets to places you might have missed. You need to repeat the process regularly as it is unlikely you will get all of them but after the population knockdown, occasional treatments will keep them from being a problem.
(insanely trying to grow ee's in zone 5 without a greenhouse)
What about a systemic like Bayer's?
Hap
Ok, this hobby is getting expensive :)
I've been learning along the way - first had started using regular potting soil - "Bad results, everything started to rot.
Then finally sprung and bought miracle-grow (moisture control), and mixture of fine peatmoss and more perlite. (sp)
Installed an exhaust fan $39.95 (kind you use in attic with automatic temp settings) and also bought the automatic vent for it - very cool... This def helped with keeping GH temp down.
Since I have installed a heater with timer and changed dirt, better shade in GH, plants starting to look so much better.
Just received my Borneo Giant in the mail - about 10" tall. Just placed it under a grow light and keeping it misted. Crossing fingers.
michaelg
You're on your way, kiddo...
Going to the poorhouse is a heartbeat away.....We have all been there...well, actually, are THERE!!
Hap
PS. Has anyone suggested that you use a very quick draining media instead of soil?
Suggestions?
Someone said that using lava rock and orchid bark was good. I have just bought a couple and I have not had time to transplant them due to our recent cold snap and having them in the house.
Hap
I'll try. Thank you.
Please let me know and I will do also. thanks
Hap
krowten thank's for the extra's that you added. I really appreciate it and good luck to you with your Elephant ear plant's in your zone.
Hap, I am going to try a systemic. From what I have read the Bonide and the Bayer have "rave" review's! Thank you so much for this added tip.
Good luck michael with your situation as well.
Rachel
They should call it the "Lazarus Powder"! LOL
Hap
Rachel, Thanks for the kind words - just lost my borneo giant to rot though. I have a friend hosting its twin, so hopefully I won't need to start over.
krowten.
So what do you think that you did wrong with the Borneo?
Hap
Might have been too much water at one time. Didn't have a problem with them last year when I was keeping them wetter than this year, but they were going through wet/dry cycles this year. Also, I've been keeping the house colder this year and maybe not as much light.
Michaelgalvin, I thought, looking from your pictures that you were using straight peat and just a little perlite, and just a few posts above this-thats what you said. Your PH is right around 3.2-3.5, and that is way too low. I think that you will start to see real problems with your aroids as the roots start to grow because I am pretty sure that they can not grow well with a PH that low.
If I were you, I would getting a soiless mix that has peat in it, but has more perlite than what you are using and-most important, has lime in it that will raise the PH to about 6.2
