I dont hink brand matters much, but size does.
Perlite boasts extensive benefits as a growing media for indoor and outdoor gardening. What is it good for? Read on to learn more about this natural rock, it’s benefits in gardening, and comparison to vermiculite.
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You dont want really small particles or the jumbo size. I would recommend medium or coarse particle sizes, with a slight preference for coarse.
One of the main benefits of hempy buckets - maybe THE key benefit - is the aeration that occurs when the water in the bottom of the bucket wicks up towards the top of the bucket.
Roots need oxygen as well as water and nutes. The more oxygen the better. Without oxygen, hydro is a swamp and your plants will die.
There are two key things to note here.
1) Oxygen disperses or diffuses through the air very easily and rapidly - even in soil or a bucket of perlite - IF - there are air spaces. There must be air spaces.
2) Oxygen diffuses/dissolves/disperses through water very slooooowly. It takes a long time for oxygen to penetrate to any depth in water. The top most very very thin layer of water will reach 100% oxygen saturation very quickly, but it is very sloooow to penetrate deeper.
The water sitting in the bottom of a hempy bucket will tend to get stagnant as the roots consume the oxygen. Thats takes some time, so dont freak out.
However, that is more than made up for as that water wicks up towards the top of the bucket. Dont think of that water in the bottom as the main source of food/water for the plant. Its just a reserve for the water that wicks up to the perlite above it. Its there so you dont have to constantly water the perlite every day.
The 'wicked' water in the upper part of the bucket is what makes hempy buckets work. It will be in the form of a super thin layer on the perlite particles. Remember #2 above. Very thin layers of water will reach oxygen saturation very quickly. The roots that are in that part of the bucket will always have all the oxygen - and water - they need - IF IF IF - there is room for air around the particles.
Larger particles will allow more air spaces. Smaller particles will end up holding more water, but its the oxygen that is critical in hydro. The more aeration you have, the better the hydro functions.