5-gallon Brewing Buckets with a spout - It is mostly about the spout for filling anything.
A cut piece of small PVC - great for stirring!
Submersible pump - Not only great for mixing nutes in your res, but I also use it to pump water out of the nute bucket (with a hose attached obviously) to feed plants (especially the ones in the back of the tent that are hard to reach when you have a trellis net installed).
Transmission fluid funnel with a 3/4 pvc pipe extension.
Makes watering easier.
I have arthritis and bending over is painful.
I also have a box cutter blade on a bamboo stake for cutting lower verge off the plant.
Handiest gadget hands down for me is the post harvest trim bin.
When o got mine a few years ago it was like 20$. Amazon now has them for 50 something. Yikes. I just did a quick local Craigslist search and there are a bunch of these used for sale for a few bucks. Check there first if you are watching your $.
I keep batches of Jack’s 321 in separate Tupperware to decrease any access to moisture in my damp basement. The Tupperware is still pretty full after 4 grows and I haven’t had to refill. I bought the Tupperware at the $1 store. The large bags the powders come in are tied up in trash bags with desiccant packs to help with moisture as well.
I also write the amount needed on the Tupperware lid per 5 gallons or 25 gallons depending on if I’m mixing for a bucket or my res.
I write these amounts on liquid nute bottles as well. The less I need to think the better.
I bought a cheap metal rack. 32” tall, 32” wide and 16” deep. Best thing for my nute storage, tools, and my 5 gallon res is on the bottom with one of those pumps and a hose.
or relaxation day it comes in pretty handy.