Bignutes
Well-Known Member
The wick I run is about 10% of pot size, the roots are contained by the pot and wick, this prevents the roots from reaching an air gap
SIP thread -- (Sub-Irrigated Planter)
- Thread starter Humanrob
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GenericEnigma
Well-Known Member
Sure, I've wondered about all this.
The roots grow around the gravels in my air gap. I imagine they stay wet, and even contribute to the wicking. But my air gap has always been more functional (less soil saturation), and less chemical (oxygen to roots) in design intent! I also mulch my soil's surface with leaves, so plenty of breathing there.
I don't know how much oxygen roots need, but mine have gotten enough in 5-gallon pots without sub-irrigation. I guess that means I don't have a strong opinion about the air gap's absolute necessity, so I am grateful you shared what you've got.
I also don't pay much attention to aerobic/anaerobic soil conditions. My vermicompost is just a huge pile of everything, full of pill bugs! The only mixing it gets is when I bury vegetative refuse therein (I get lots of sprouts when I top-dress with it!).
Is your soil pretty standard stuff? Do you ever have issues with water wicking all the way up to the soil surface from the bottom of the wick? How deep is your soil?
I guess what I really want is to see your whole setup!
weedstoner420
Well-Known Member
Interesting... @Bignutes I just checked page 1 of your grow and yeah, no holes in the bottom of the soil section, only a few small holes in the bottom of the wick cup. Yet the commercial sips (Earthbox/Growbox) and most of the diy ones have a ton of holes in the bottom of the soil section...
I know the soil can get oxygen from above, and it doesn't really need that much (I suspect the excessive use of perlite/aeration in soil for cannabis may just be a crutch for growers who tend to over-water (which is also why a lot of people, including myself, gravitate towards sips)). Like, I have some houseplants in big containers with no drainage, and as long as they don't get too saturated/anaerobic, they're fine. And like you said, there is no air gap in nature.
So the air gap/holes at the bottom of the soil just serves to allow more air to reach the lower layers of soil. Is it needed? No. Does it benefit the plants? Dunno, would be curious to find out...
Do you have an overflow/drain hole in the bottom section of your sips, to prevent the water line from getting above the bottom of the soil section? Or is that not even necessary if you don't have any exposed soil at the bottom of the container?
I know the soil can get oxygen from above, and it doesn't really need that much (I suspect the excessive use of perlite/aeration in soil for cannabis may just be a crutch for growers who tend to over-water (which is also why a lot of people, including myself, gravitate towards sips)). Like, I have some houseplants in big containers with no drainage, and as long as they don't get too saturated/anaerobic, they're fine. And like you said, there is no air gap in nature.
So the air gap/holes at the bottom of the soil just serves to allow more air to reach the lower layers of soil. Is it needed? No. Does it benefit the plants? Dunno, would be curious to find out...
Do you have an overflow/drain hole in the bottom section of your sips, to prevent the water line from getting above the bottom of the soil section? Or is that not even necessary if you don't have any exposed soil at the bottom of the container?
meangreengrowinmachine
Well-Known Member
The earthbox and other generic grow box designs have them also, and they are designed to have a cover on the soil. I have for sure seen a lot of people have success without the holes though.
Hollatchaboy
Well-Known Member
So if the air gap isn't needed, why waste the space on nothing? If I diy a sip, do I leave out the air gap?
meangreengrowinmachine
Well-Known Member
The inntainer design does not call for it and I built 6 of them to the exact specs. 90% of the time they worked great but I did end up having issues a few times with things (I think) just staying too wet.
GenericEnigma
Well-Known Member
Plants need actual O2 as well. It's used in breaking down sugars as part of cellular respiration. It's not part of the typical 6CO2 + 6H2O + light = C6H12O6 + 6O2 process to make sugars, so it's not commonly known. But when a plant needs to use its own sugars, O2 is needed (if I understand correctly).
GenericEnigma
Well-Known Member
Seems like an extra gallon of soil might fit in there.
I will be maintaining the air space in my wicking bed. As wet as the soil is, the last thing I need is more surface area contact between soil and water!
But for SIPs with wick baskets? Dunno. I would think the wick size and soil makeup might drive that decision.
myke
Well-Known Member
No,air gap is there to stop water from hitting the inntainer and soaking the roots.
So instead of calling it an air gap.Call it a failsafe, to stop us stoners from overwatering lol.
Bignutes
Well-Known Member
I can see the level of my reservoir because it’s a clear tote. It’s covered with a black garbage bag so no light gets in. Peel the bag back when I fill it. There is a hole on the top that I use a funnel to fill. I wanted to maximize rez size for less frequent fillings. Wicks about typical size.
I can fill the 25 litre rez up completely and because the 5 gal pail sits on top of the rez the soil can never be submerged.
Bignutes
Well-Known Member
I agree, the air gap is more functional to limit the wicking going on if I’ve got your design down.Sure, I've wondered about all this.
The roots grow around the gravels in my air gap. I imagine they stay wet, and even contribute to the wicking. But my air gap has always been more functional (less soil saturation), and less chemical (oxygen to roots) in design intent! I also mulch my soil's surface with leaves, so plenty of breathing there.
I don't know how much oxygen roots need, but mine have gotten enough in 5-gallon pots without sub-irrigation. I guess that means I don't have a strong opinion about the air gap's absolute necessity, so I am grateful you shared what you've got.
I also don't pay much attention to aerobic/anaerobic soil conditions. My vermicompost is just a huge pile of everything, full of pill bugs! The only mixing it gets is when I bury vegetative refuse therein (I get lots of sprouts when I top-dress with it!).
Is your soil pretty standard stuff? Do you ever have issues with water wicking all the way up to the soil surface from the bottom of the wick? How deep is your soil?
I guess what I really want is to see your whole setup!
My soil is a combo of compost, loam, peat, aeration. The 5 gallon pails are 14.5” high. At the start of the grow water wicks all the way to the top of the pail. As I get into deep into flower the top 4 inches is not parched but somewhat dry.
If you want to set my setup look at my grow journal.
Bignutes
Well-Known Member
No overflow or drain hole, just stop filling as I can see into the clear reservoir tote, soil sits on top of high water point
meangreengrowinmachine
Well-Known Member
Can you post a link? I'm on mobile nearly all the time and it doesn't show signatures or anything. I would love to check out your set up. I had made some 5 gallon SIPs just within other 5 gallon buckets. For me I ended up wanting to go with more soil. But did grow some very nice plants in them.
weedstoner420
Well-Known Member
If you turn your phone/screen sideways it changes the format and shows people's signatures
myke
Well-Known Member
I can’t see any sigs with my I phone regardless what position the screen is in.
Bignutes
Well-Known Member
Here it is:
SIP Grow
To start I used 25 litre totes for the reservoir, yoghurt containers for wick, 5 gallon pails for soil, garbage bag to cover SIP. Cost $12 per SIP. In the past my reservoirs were too small so these will triple the capacity of an old style.
www.rollitup.org
I had a similar experience. If I’d do it again I’d veg for less time in 5 gal.
meangreengrowinmachine
Well-Known Member
Yeah I vegged mine way to long also