Quote:
Originally Posted by Orchid Whisperer
Hi Naoki
I've read a few posts and articles about using aspirin on orchids. I'm wondering what benefits you are seeing, what dosage you use (I've heard 1.75 full strength aspirin per 2 gallons water; does this sound right?), and do you apply to the leaves, to the roots, or both?
Similar questions for Trichoderma. Is this in the form of a seed or root innoculant? Would a compost starter innoculant be likely to include trichoderma? How do you mix, apply, and to roots only, or both leaves and roots?
Thanks!
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As you probably know, there are quite a bit of scientific evidences showing that Salicylic Acid (SA) is used to signal immune response to wake up. Similarly, SA also helps in stressful conditions such as drought. Aspirin is a modified SA: acetylsalicylic acid (ASA). There are some experiments showing ASA also has similar effects in some cases.
So I use it when the plants are stressed, at an early stage of infection, during deflasking, and when I receive new plants. As with the preventative method, it is difficult to assess the effect. I feel like that some disease seems to stop without cutting the leaves or other chemicals or higher acclimation rate, but it can't be differentiated from a placebo effect (in other words, don't expect too much). 1-4 tablets (325mg) per gallon is probably a reasonable amount. I have used a higher concentration, and I didn't see anything negative. There isn't any study with orchids, so the dosage is a guess from studies with other plants. I spray to the leaf and drench the pot.
There are several strains of Trichoderma, and their effectiveness differs even within the species, T. harzianum (the commonly marketed ones). There is also another species
T. atroviride, which is better at a lower temperature. This might be useful for high altitude/cool/cold growing orchids, but I don't have this. So I'm not sure if the compost starter will work or not. I use RootShield (and follow the suggested dosage). I think it is dormant fungal spores, right? I drench the plants. But when I get really weak imports, I soaked them in the Trichoderma solution for a couple hours. The following post by Lars is one of the reason why I tried this method with my recent Malala import:
Importing plants: The effect of Trichoderma on root development
From reading a couple scientific papers, some Trichoderma does indeed seem to have an ability to promote root growth. I have used this only once for the purpose of acclimation. I was expecting that the drop rate of Malala import would be 50% or so from the posts of others, but I have lost only 1 out of 10 plants (another was practically dead on arrival). They have stabilized and started to grow after 2-3 months, but some of them may still die. I'll try this more in the future.
I'm trying a method to home-brew Trichoderma with oat because it is pretty expensive. My first trial didn't go so well, and I haven't found a time to try again.
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