I have tried almost everything I have read both on this forum and out there in the internet and I just cannot get rid of my extremely bad aphid issue on my seedlings from over the summer. I felt they were too young to put outside so I am trying to overwinter them in my indoor grow room and I feel that I am going to start losing them because they are just covered with aphids from head to toe. I have tried dish soap and water, rinsing them off and applying flour and chili powder to the leaves, Using a commercial aphid spray which ends up browning the leaves and then they come back, pinching and crushing them with my fingers, and the list goes on.
I have two ideas left that I have not tried and am wondering if anyone has experience using them:
The first is drowning the aphids by completely submerging the seedlings in water for an extended period of time - say 4 - 24 hours. I’ not sure how effective this would be and I am worried that it may drown out the seedlings too. The seedlings range from 6 to 3 months old if that has any effect on it. It may be the safest and possibly easiest for me to do since I have about 200 seedlings to do which are in 3’ pots.
The second method is applying a light application of Bayer Advanced All-In-One granular fertilizer. It is a 6-9-6 slow release fertilizer which claims to be able to kill aphids (among other things). I do not usually use fertilizer on my seedlings so this will be the first feeding for them. I am hesitant because it says on the label it is not intended for potted plants. If I use a 1/2 dose, will it still be effective yet safe for the plants?
Any thoughts or additional indoor methods of controlling aphids would be appreciated. If all else fails, I will probably end up putting them outside to let winter do the job for me but then I fear that I will lose many of them due to shock or because they don’t have the built up cold hardiness yet.
I second the suggestion. Safer’s dehydrates the little critters.
If the weather is not too cold, most of the aphids can be washed off – outside – with a gentle spray from a bottle or garden hose. Then the Safer’s can finish off any stragglers.
Karl
Just a follow up on Joe’s comments. My first instinct would have been to go with a soap since its indoors, but imidacloprid is used indoors in some products, and on pets as well. Imidacloprid General Fact Sheet so it probably is relatively safe. (Am I understanding correctly that your grow room is inside your home?)
The Gardeners Magazine 3rd ser. 12: 633 (Dec 1841) Tobacco-Paper is preferable to tobacco to fumigate with, because it is cheaper, and does not burn so fast. (Gard. Chron., vol. i. p. 213.) Tobacco-Water will kill all aphides, but much more effectually when warm than when cold. (Ibid., p. 617.)
My grow room is in the basement in a corner of the utility room. So its very out of the way of pets and other humans. In the past I successfully used a weak tobacco water on my roses but I think someone on this forum told me that while it is good at killing unwanted critters it does something detrimental to the rose plant too. I used to also use it to get rid of the mites that I used to get on all my houseplants to great effect.
Thanks for the suggestions. I will add them to the list to start trying and hopefully I can get one to work either completely or at least get them to a manageable level. If anyone has other suggestions please continue posting.
Nicotine is toxic to roses so nix the tobacco juice.
As Joe says, imidcloprid is the way to go. My dog wears a Seresto collar made from 10% imidcloprid for eight months out of twelve. He never gets aphids.
Another vote for something with Imidacloprid as main ingredient. Yes I echo the bee killing, but you are using it indoors where the aphids have the upper hand-no natural predators (or bees). I also sprinkle a dusting of it under the beds of the feral cats and have not had a trace of fleas (three cats) for approx. 10 yrs. But other than really limited use of it for termite control around the base of the house (in Feb) do not recommend it because it does kill bees. If it is unusually warm then we do find some dead bees around the foundation.