In the culture of cannabis, hydro weed means meaning hydroponically
grown, or indoor, and “weed”, meaning...umm, err...marijuana.
Cultivating Cannabis indoors traditionally has to do with growing the
plants in a soil-like medium and adding fertilizer when the plants are
Cultivating hydro weed indoors is more complicated and expensive than growing outdoors, but it allows the cultivator complete control over the growing environment. In order to grow plants indoors, a growing medium (soil or growing substrate), water, nutrients, light and air need to be supplied to the plant.
Using hydroponics, the plants are grown not in dirt, but usually in what's called rock wool or perlite and the cultivator should maintain as close to an ideal atmosphere inside the grow-room as possible. The air temperature should be maintained within a specific range, typically with deviations no larger than 10 Celsius with a cooler night and warmer day.
Adequate levels of CO2 must be maintained in order for the plants to grow most efficiently. It is also important to promote vigorous air circulation within the grow room, which is usually accomplished by mounting an extraction fan and one or more oscillating fans.
The benefits of growing hydro weed are numerous. It's a completely controllable, safe environment where the farmer, you, calls the shots. You decide the strain, the potency and the output levels. The undertaking itself – aside from the obvious benefits after you've harvested – can be quite educational and fun.
If this sounds complicated, or it's new to you, that's okay. Any reputable hydroponics dealer will help you learn what you need to learn the best way to grow hydro weed.