Journal archives for June 2023

27 June, 2023

3.5 years and recipe for organic insecticide

An interesting journey of late.

Regarding iNat, I feel their technical leadership has sort of lost the plot and invested in some questionable technology decisions and is apparently not open enough to discuss them. Happens a lot when you get ego involved with the stresses of an established platform and user base, things become change averse and personal domains reign. This is sad. I became aware of and temporarily engaged with lobbying for improvement on those issues when some rare first observations I made in Hainan were modified and the original labels lost. Now I am less motivated to invest in the platform and am more interested by learning.

Three and a half years of gardening has fielded some success and failures. A lot of plantings were lost to bad tenants which yielded a court case and much associated kerfuffle. Still awaiting a ruling but confident of some degree of financial reparations. Completed extensive repurchasing and replanting as a result, a huge time investment. Three water features have been installed and are receiving increasing numbers of visitors. Unfortunately there are some roaming cats around which may be keeping the fauna down. I have been scaring them when seen, but need to find a solution. The ringtail possum formerly resident in a bird's nest fern was electrocuted on a nearby power line and died. It was a female with no young in its pouch. An exterior planting of 3+ years vintage was destroyed by someone walking on it recently, despite being staked and in a raised bed. Sometimes you just can't win. My callistemon caught thrip and I had to prune them back heavily. After realising the organic insecticies were only a single active ingredient (Potassium laurate) and overpriced I launched a chemistry mission to obtain bulk quantities of Lauric acid and Potassium hydrochloride and am preparing to mix them for a prolonged treatment. According to a chemist friend the recipe is as follows.

Preliminaries

  • The active ingredient is Potassium laurate.
  • According to an environmental scientist friend, that is a potassium salt and I am told that potassium salts occur naturally in the body.
  • Based upon commercial retail product labeling, the target solution strength is 2% in water and this has been certified organic by some authority or other.
  • Based upon my recent research, you can't buy it at full strength as far as I know, but you can buy two precursor chemicals: potassium hydroxide and lauric acid.
  • It's an acid-base reaction. Therefore you need to work on equal molarity not equal weights.

Recipe

  1. Obtain potassium hydroxide and lauric acid
  2. Weigh out 20.03g of Lauric acid, dissolve in 200mL water.
  3. Weigh out 5.61g of Potassium hydroxide, dissolve in 200mL of water. This will get hot so you will need to wait until it cools down.
  4. Mix the two solutions. It will give you 400mL solution containing 23.84g potassium laurate (60g/L).
  5. You can then dilute it to whatever you need.

Excepting my own efforts I have visited some interesting gardens and begun to network with a few more interesting groups, chiefly fern people who are as eccentric and varied as you would expect. I was the new blood and I'm over 40.

I have also begun a journey toward watercolours, among similarly advanced peers, and with minor success. I completed one simpler botanical watercolour with which I am relatively pleased... perhaps there may be more in future. A lot to learn, and my drawing which is fundamental remains poor.

Although I will have to leave the garden again soon, I have begun propagating a few species from seed: one elegant thin-leafed Lomandra cultivar with seed collected in the garden, 100 Cordyline stricta (also from the garden) and a fair number of Cordyline indivisa (purchased). In addition, I have begun propagating some ferns - predominantly from spore, about 8 species, but also some from leaves. I've purchased a number of large Platycerium and Asplenium nidus from individual sellers (really - why would you sell such a thing?) to bolster the garden's existing stock, and collected some other species mostly gifted.

Posted on 27 June, 2023 23:04 by pratyeka pratyeka | 0 comments | Leave a comment

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