A gardener should be able to formulate some inputs in order to cut on costs. A good organic pesticide can be made from water, bitter plants like chilli, tobacco leaves and mexican marigold and barsoap. Simply heat the bitter plants in water to extract the active principles then discard the leaves. Cut pieces of barsoap and heat to dissolve it in water. This would act as a carrier for the pesticide. This spray is quite effective against a broad range of insect pests.
Thanks for sharing the tip, @remnant! I usually use Blue Death, and really don't like using it because I do wonder how horrible it is on these creatures. I know the idea is to get rid of them, but I don't necessarily want them to suffer. I mean, even the name sounds horrible, doesn't it LOL?
There is a region here that has tobacco farming as the main industry. Old folks there say that remnants of tobacco plants after harvesting are piled up and sometimes used as pesticide in the home. Even the tobacco leaves that they hang for drying drives away insects particularly mosquitoes. I think that is a good concoction for an organic pesticide except for the bar soap. Maybe I would use dish washing soap which is milder in potency. However, there is no way I can get tobacco leaves for that tobacco region is 10 hours away from here.
I don't know if it's an old wives tale, but apparently sprinkling salt and pepper around your garden will help to deter insects and spiders. I've never tried it myself and don't know if it works, but thought I would chip in with that in case it helps anyone. I've also heard that you can use garlic spray, but I don't know where you would get it from.
Well it may be cheap - but as a long time gardener and also one with many, many years of organic gardening experience - I have to say that - there is absolutely no way that this recipe could be described as a “ good “ organic pesticide - as apart from the bar soap not being a good idea - the biggest concern would be the tobacco content - in fact so much so - that I wouldn't even consider using anything that contained tobacco in any form around the garden - let alone recommend using it. Particularly as - although tobacco is natural and was used in all forms many decades ago as a base for both pesticides and fertilizers - you won't find many gardeners - organic or otherwise - willing to use it these days - for the simple reason that - not only is it extremely toxic to all living things - including humans - but it is very definitely not something that should be used in the garden - as it can kill all beneficial insects, animals and humans - due to its high toxicity as well as - kill and cause a number of diseases in the solanaceous - nicotine/deadly nightshade - plant family - particularly tomatoes, peppers, potatoes, eggplants etc and therefore - as there are a whole range of other plants that are particularly sensitive to nicotine - like roses for instance - and it is very difficult for the average gardener to know which plants they can safely use it on - its generally best avoided in any form.
I've heard it said that wood ash can be a great pest repellent. I've never used it myself but I read somewhere that it has been used in the past and the results were good. You can apply it directly on infested parts of plants or you can mix it with water if you want to. And it can be good for the soil too since it contains potassium.
Like @Corzhens, I've used mild dish soap. I had a problem recently with pests on my mandevillas. I believe they were spider aphids or something like that. They were tiny and black, which I noticed because the flowers are white and pink. I didn't notice the infestation until I uploaded some pictures to the computer, then it became quite apparent. I mixed up some mild dish soap and water with a little white vinegar, and sprayed the plants. The pests were gone the next day. I'll make up another batch and reapply in a few days, just to ensure that they're gone.
