By Luke Sumpter


Research and development by the United States Department of Agriculture (USDA) during the 1960s led to the creation of the first hydrogel prototype AKA Super Slurper. Early products that followed were granulated sugar-like powders—tiny plastic crystals that resembled sludge when wet. Continued private research and development have led us to biodegradable crystals with tremendous water absorption capacity.

Water-absorbent polymers, superabsorbent polymers, and hydrogels are one and the same thing. However, the best modern, long-lasting, horticulture-grade polymers can hold 30–60x their own volume of water—without leaving behind any toxic by-products in the soil.


Polyacrylate polymers are usually sodium-based. They can be commonly found in diapers/nappies. The trouble starts with PACs after about 6 months as they begin to break down. Not only is this probably too soon for plants, limiting the number of wet/dry cycles, it’s also a potential harvest spoiler. These polymers release nitrogen at the worst time, typically when most photoperiod strains are in late bloom. Or worse, during flushing.

In contrast, potassium-based polyacrylamides (PAMs) take 5–7 years to deteriorate. Today, many are biodegradable. You can grow any strain you like again and again. PAMs can help a grower conserve water and fertilisers long-term. Best of all, these polymers are genuinely environmentally friendly. Guaranteed not to delay or taint your harvest.

Polymers Absorbent Water Culture Cannabis


Auto growers can probably get away with using the crystals cut from packs of diapers. Given that most autoflowering hybrids have a complete lifecycle of somewhere between 8–12 weeks, time is on your side. So you don’t really require polymers with a long lifespan. Pretty decent grow hack for one auto crop.

But if you plan to grow outdoors for 6 months or more, the cultivation of some photoperiod monster plants demands higher quality polymers. You need superabsorbent gel or powder that can maintain effective wet/dry cycles for a period of years, rather than months. Alsta Hydrogel by Chemtex Speciality Limited is an excellent eco-friendly option.


A cup full of superabsorbent crystals goes a long way. The most effective way to use hydrogel is to hydrate it first. Preferably with a light nutrient solution. Then, mix the jelly with the bottom third of soil in a large container or deep hole. Alternatively, Just a few grams of dry powder needs to be added to the soil mix. See the manufacturer’s guidelines on the packet or visit their website for specifics.

Essentially, you are creating an emergency reservoir for the plant's roots to tap into when they need it most. If you expect prolonged drought conditions, you can mix polymers throughout the soil matrix to improve the overall water retention properties of the substrate. The added bonus is a better-aerated medium and more efficient use of fertilisers.

Not every outdoor crop is a level green field with rows of cannabis plants. Plenty of guerrilla growers are cultivating marijuana on sloping hills. The secret is they’re using hydrogel to reduce water runoff. Similarly, hydrogel comes in handy if you don’t have the luxury of planting close to home and can’t make daily trips to water plants. During the hottest, driest summer months, polymer reserves can prevent plants from drying out and wilting for a day or two longer.

We have seen some promising results with a new kind of nutrient film technique (NFT)—such as hydrogel film that has been used to grow some fantastic hydroponic lettuce in Japan. Unfortunately, this new grow tech has struggled to produce bountiful harvests of larger-fruiting plant species. For now, water-absorbent polymers are exclusively soil enhancers.

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All-In-1 GrowCaps are a stellar example of how polymers can enhance cannabis growing. These GrowCaps feature capsuled polymers that gradually release nutrients over time. They contain all of the nutrients that cannabis plants require over the entire grow cycle, but they don’t dump it into the soil all at once.

The polymers slowly break down over the natural growth cycle, meaning the correct nutrients are always available in the optimal quantities. In this regard, polymers have made growing cannabis more accessible than ever before. Novices need not worry about juggling nutrient ratios and feeding schedules. It’s merely a matter of placing GrowCaps in the soil and watching the magic unfold.

All-In-1 GrowCaps don’t just make feeding easier, they also reduce water usage by 30%. They absorb water with incredible efficiency and release it back into the soil slowly over time.

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