A little bit of history, and zooming out might help @FungusGnat
Take a look at where cannabis grows (or used to grow) wild. It’s in nature, and it needs no nutrients added. It’s able to do this because other plants and animals are adding nutrients as the cannabis is taking it out, and vice versa. It’s a symbiotic relationship. This is largely what tree/fruit/flower growers attempt to mimic. Natural conditions, with soil fortified with everything it needs, to slowly release the nutrients to the plant over time, the same way that it’s done in nature.
Liquid fertilizers are largely viewed as bandaids, and cheats. If you’ve met any tomato growers, or big pumpkin growers, none use liquid fertilizers. Even miricle-grow is viewed as “amateur hour.” Most of the liquid fertilizers are unstable, so they need to add other products that plants need in order to keep the nutrients in solution and not precipitate out. These added products eventually build up in the soil and are bad for plants. They also have a tendency of killing off bacteria, microbes, and fungi that the plants need. Once you add the liquid fertilizer, the plant often lacks the ability to hunt out the nutrients naturally existing in the soil, and so it creates a treadmill.
Cannabis growers, historically at least, had different issues. In prohibition times grows moved largely indoors. When indoors, you lacked the ability to have 25-50 gallon pots that can hold all the nutrients the plant needs. Growers also needed to be careful how much outside product they were bringing in. An apartment dweller with some balcony flowers that’s getting pallets of soil and soil amendments would look really suspicious. Added to that, cannabis growers were constantly looking to push a plant to it’s limits. Flower faster. Grow quicker. Grow bigger. So getting nutrients directly to the roots, quickly, with a small footprint, mattered. So small growing containers, that didn’t have enough nutrients naturally, and addition of chemical nutrients to supplement the fast growing, that came in small bottles that could be disposed of discretely, was crucial. This growing method would be considered heresy by a tomato grower, or a champion cucumber grower, or even a bonsai grower.
There’s been a bigger movement in the cannabis world toward living soil and organic growing, now that appearances and footprints are less of a concern in some areas. But alot of the growing culture’s roots (pun intended) have stuck around.
So the “laughing” the store owners were doing to you is, at least in that gardening world, not surprising. It’s the equivalent of someone growing tomatoes in dead soil and needing to spray miricle grow once a week to keep the plant alive. There’s a better way. But, at the same time, none of those tomato growers can get the speed of growth that most cannabis growers wanted. And they didn’t have the cultural, historical, and learned baggage. Meanwhile, if you step foot in a hydro store by someone that’s been growing in their closet for 20 years, they’ll aknowledge the benefits of living soil, adding compost, and powdered nutrient supplements, but will also explain to you the benefits (and drawbacks) of a more hydro based approach (or a soil based that uses alot of liquid nutrients).
As far as perlite goes . . . yeah, that stuff is kinda rough. There are alot of other alternatives. The eco footprint of perlite isn’t great, it’s expensive, not the best for your health or the environment. Lava rock is an alternative, but not as light. Rice hulls help, but keep in mind they will start to break down over time. Which may not be a bad thing. But also keep in mind, the rice hulls aren’t exactly an “eco wonderland” in their production either. It’s a byproduct of the rice grower world, and they can’t get rid of the stuff. Most farmers either burn it on their property (sometimes illegally), till it into the soil (sometimes too much), or have to pay someone to remove it. That person they pay to remove it often takes it to a dump, or occasionally turns around and sells it to you, making money off the farmer and you. And depending on the source, it may come with chemical additives (not too common with rice hulls though).
