Check out my DIY SIP grow system for cannabis. SIP stands for sub irrigated planter and it can grow just about anything but cannabis is my favorite plant so here goes!
First let me say I did not invent this. It came out of reading about and watching videos about diy self watering planter beds. Most of them were about growing vegetables and I adapted it to growing cannabis in smart pots.
The SIP growing system is a great way to water because it eliminates over or under watering. One of the biggest problems many growers face is getting watering right. If plants dont get enough they can shrivel and die. If they get too much the roots dont get enough oxygen and plants are stunted.
So how about trying an easy to build sub irrigated planter that gets watering right each and every time?
Not only is it a really easy DIY project but it is also inexpensive to set up. These diy self watering planter beds can easily be automated if you want to. But they can also be run totally passive with no pumps or electricity needed.
My DIY SIP Grow System
In the video below I show my system at work. It is a bit more complex and not passive but it is giving great results. The great thing is even if it were totally passive it would still give the same great results.
How To Set Up A SIP Growing System
Have you ever cleaned up a spill with a paper towel? Then you know it wicks and soaks up water by capillary action. Water is pulled into the napkin and this is the principle that makes a SIP work.
Capillary action (sometimes capillarity, capillary motion, capillary effect, or wicking) is the ability of a liquid to flow in narrow spaces without the assistance of, or even in opposition to, external forces like gravity.https://en.wikipedia.org/wiki/Capillary_action
Water moves from a wet medium and is wicked up by the bottom of a smart pot. You dont even need to understand how it works because it just does it.
There are just 2 things to keep in mind building a SIP. First you need a porous medium like hydroton or perlite. River rocks, gravel or pebbles wont wick well so dont use them. Besides they are really heavy.
Second your smart pot needs to be above water or your plants will drown. It will all make sense once I explain how to build one.
What You Need For Your DIY Sub Irrigated Planter
You will need a container. It can be a tote, cat litter box or mixing tote like the ones I use in the video. It needs to be deep enough to add a layer of grow media for your wicking bed. And it needs to be water tight because we are going to fill it part way up the medium with water.
Get yourself a smart pot and medium to fill it with. 2 or 3 gallon smart pots will grow big plants when filled with coco or a coco mix and there is no need for anything larger unless you are really growing trees. You can use straight coco or you can mix it with some perlite. You dont want to use anything like garden soil because it is too heavy and will compact when watered.
Sub Irrigated Planters Are Simple! Dont Overthink it!
That is all you need to build a basic SIP that is hand watered! You probably will want to add some automation so you are not always hand watering. This can be from a gravity fed reservoir and float valve or a flood and drain type system like I am using.
Here is a good starter thread I found online: https://forum.grasscity.com/threads/noobwannbs-self-wicking-smartpot-ghetto-setup.1151159/
DIY Recirculating Smart Pot SIP System
Most Sip systems I have seen are hand watered or at best fed through a reservoir with a float valve. Also most of the systems I have seen use organically amended soil of some type and generally are not fertilized beyond that.
The most common systems seem to be made with double buckets and use a cup for a wick. A few growers started experimenting with smart pots and I really feel this is the way to go.
Why A Smart Pot SIP System And Why Recirculate?
Smart pots naturally wick moisture and they can breathe. They also root prune and yield more than a similarly sized hard plastic pot or bucket. They are the ideal container for a SIP system.
Since I am an old hydro guy the idea of still water scares me. I want my water to be moving and I also want my water to supply nutrients. Moving water carries oxygen while still water is anaerobic and stagnant water carries a risk of pythium and other diseases.
Roots are going to eventually make it out the bottom of the smart pot. Since it is not laying on a hard surface there wont be much root pruning. Roots sitting in stagnant water is unhealthy and never a good thing. This is probably the best and most important reason to recirculate your nutrients.
Flood And Drain SIP?
If you watched the video above you can see that I have built a recirculating SIP system and that I am using 3 gallon smart pots. I used 20 gallon mixing totes that I bought at Home Depot for about $13 each. They are about 2′ x 3′ and I used 3 in my system. There are 2 for my plants and the third is placed below them as a reservoir.
Some Recirculating SIP Pictures
The planter totes have been fitted with ebb and flow fittings. This system can be used quite readily on flood and drain tables but since it runs continually there is no ebb and flow.
I use the 3/4″ fitting for a drain and the 1/2″ to fill the totes. Inside the reservoir I have a 400 gph Ecoplus pump which cost around $25. I installed the included 1/2 output fitting with a short piece of tubing that went to a tee and connected the tee to 2 short pieces of tubing that connect to the flood fittings.
If you are only running one tub it is much simpler to hook up of course.
Make sure you get the with the screw in plastic screens.
One screen keeps the water from spraying all over and the other will keep the perlite or hydroton you will be using out of your reservoir.
I allow my drain to fall into the reservoir below to add some aeration but if you dont like the sound of water running you can put some tubing from the end of the fitting into the reservoir. Personally I find the sound very relaxing.
You want the totes to be on a level surface so water will spread throughout the tote and you dont have any high or low spots that could result in uneven watering. After you run the pump and make sure everything is level and nothing leaks it is time to fill your tote.
Filling Your SIP And Smart Pots
You will want to add about 2-3 inches of medium. I used growstones but unfortunately they no longer make them. I recommend using chunky perlite if you can it just because smaller pieces could clog your drain screen.
Your fitting should have come with some straight extensions to adjust flood depth. You may want to use them but I did not need to. What you are after is a water level that stays about an inch or two below the surface of your fill medium.
This is important! You do not want your smart pots to sit in water! Your pots should sit on top of the perlite and the stones will allow the pots to wick water from them. The water should be below the surface.
Use Smart Pots For Your Sip
Smart parts are the natural choice for a sip grow system because they wick water. You can use plastic pots if the bottom holes are placed in the medium. But you wont have to worry about placement with a smart pot because the whole pot is a natural wick.
Smart pots filled with coco can grow really big plants. I cant see using anything bigger than a 5 gallon pot and for most grows 2 or 3 gallon pots are plenty big enough for anything short of an actual tree.
Use Coco! Avoid Peat And Potting Soil Mixes
I recommend using coco instead of peat based mixes. Peat is very acidic and they buffer it with lime which leaches out over time and it becomes way to acidic to grow healthy plants. Coco on the other hand naturally is around a 6.2 pH which is great for growing. It also doesn’t compact like peat.
My “soil” is what is called a chow mix. It is about 50% coco and 50% growstones. You can use straight coco but I prefer a bit lighter of a mix. Once you fill your pots place them on top of the medium and make sure they have good firm contact with it.
What Size Plants In Your DIY Self Watering Planter Beds?
It depends on whether you are going to be vegging in your SIP or are getting ready to flower. You can do either. If you are planning to flower you want well vegged plants, preferably they are already in your final smart pot. However you can transplant easily into coco from a smaller pot.
You can plant seedlings or rooted clones in your smart pots too. Because they have a limited root system you will need to top water them for a few weeks until their roots get to the bottom of your pot. From then on it is best not to water from above anymore.
Also, water sparingly around the stem to encourage roots to go deeper searching for water. If you over water you will have a wet pot with a plant too small to take it all up. Not a good or healthy situation for any plant.
Timer or Not?
When I first started running my SIP I was running my pump on a timer. One hour on and 3 off but I found the system worked better running full time. Your pots should feel moist on the bottom and dry higher up.
You may notice the top of your pots starting to look dry. Stick your finger in and make sure it is moist below the top few inches. You want your soil to be at what we farmers call field capacity. This is when soil has the right air and moisture level. It will be moist enough to hold some shape when you squeeze it but there should not be any water running out when you do.
Originally I had plug flats on the tote bottoms filled with media to raise the smart pots up but I have removed them as they really were not needed. I was not sure if I would have the pots too close to the stones but it turned out they can just rest directly on the media without getting too wet.
Feeding Your Smart Pot SIP System
You can use any good nutrient mix or dry salt based nutrients depending on what you like. I use and recommend Green Planet nutrients
They also make an organic certified one part called Medi One people are getting great results with.
Canna would be another good choice. I like their coco specific nutes but their Aqua Vega and Flores works great in recirculating systems.
For salts Maxigro and Maxi Bloom are very popular powders a lot of people use and like.
What ever you choose please bear in mind that your nutrients will be passing through your media continually. So you dont want to use anything with heavy organics in it like bat guano, fish or blood meal or other things that will get funky in your reservoir or planting bed. You can use lighter mixes like the Medi One and you can certainly add microbes but dont use heavy organics in this system. Even if you are hand watering they will create problems in a SIP.
Problems With Sub Irrigation Planters?
I really dont expect to have any major problems with my SIP grow system and you should not either. The only thing that comes to mind is the possibility of algae building up on the irrigation bed itself. Coco is fairly resistant to this unless it is kept over watered.
But the perlite media is in the light and has nutrients running through it so it could start to grow algae. While it is not really harmful it is unpleasant to look at. If it develops I will cut some pieces of panda film to cover it. Landscape cloth is another possibility that breathes and wont let much light through.
I will continue to update this post as my grow progresses. I usually do grow updates weekly so you might want to bookmark it and check back.
DIY SIP Grow System – Weed Wars – Revenge Of The SIPS – Day 14
Everything has been doing great and I am really starting to get excited about this SIP system. Today is day 14 and the plants have begun to flower. PPMs, pH, and temps have remained very stable and the plants are off to a great start. I have not had to water at all and that is a really nice change. Sometimes simpler is better.
Revenge Of The SIPS – Day 21 Flowering Is Full On
I have to say that my SIP planters are working even better than I expected! Everything is in full flower. The Death Bubba and Black Banana are already starting to show trichomes. The rest of the plants wont be far behind.
Day 28 Recirculating SIP Planter
Everything is working great. Plants are healthy and watering is on point. They are praying and putting on trichomes.
SIP DAY 35 GROWING CANNABIS IN SELF WATERING PLANTERS
Everything is looking great! Plants are stacked well and getting frosty. My self watering planter bed is working perfectly! Even watering and not too wet or too dry!
Revenge Of The SIPs Day 42 Plants Are Rocking!
Plants are looking fantastic on day 42. Everything looks the best I have ever seen it. Watering is on point and the Green Planet nutes are doing a great job.
SIP Update Day 42
I have been running this system for a while now and I feel it is important to update how things are going. The system works great and plants are doing very well. But I am going to make a revision.
The large growstones work great but the smaller ones are problematic. They tend to clog the drain. They dont totally block it because I have a screen over it. But they restrict flow to the point where the water level rises too high.
After several attempts to rectify the problem I decided to remove them entirely. Since large growstones are no longer available I recommend using hydroton instead. I know I recommended perlite as an alternative. I think using perlite would cause the same problems, so do not use it. Even the chunky stuff will have a lot of small particles in it and perlite breaks and can crumble easily.
I will be unveiling a system that avoids the use of any kind of stones at all. Before I do I need to test it though. Unfortunately I can not do it while this grow is going on.
If you look at the pics below you can see the small stones are gone. The plants are sitting on top of seed flats and above the water level. As a temporary wick I placed a 2 gallon smart pot under the plants and submerged the other end in the tote. This works well enough for the meantime. If you look you can see the flood and drain fittings in the tote.
Simply raising the plants up to do this was hard on the tops above the net so any other adjustments will have to wait until the crop is done in about a month.
Day 49 Flushing Begins
Day 54 Flushing Death Bubba, Black Banana, Biker Kush, Tropicanna Cookies
Flushing continues and plants are starting to fade. I turned my DIY SIP Grow System off because I decided to flush from the top manually. There is no way to get a proper flush running a bottom feed system.
I think these girls will be finished by day 63. There are still white hairs growing but also a lot going brown too. They have had 2 heavy flushes and run off was at 90 ppm. Since my tap water is 30 ppm so there is not much left in the pots.
Now it is time to get out what is in the plant itself. Usually there are a couple of weeks stored reserves. The plants should still be making some fresh white hairs when you flush. That way they can use up what the plant has stored.
DIY SIP Grow System Day 61 The End Is Near
Today is day 61 and the end is near. Not for my DIY SIP Grow System but for these plants. My system has performed above and beyond my expectations!
The only glitch was using stones that were too small in one of my totes. This is easily corrected and the next run will have larger stones in it. Other than that everything got just the right amount of water throughout the grow. There was no under or over watering and that was what I hoped to accomplish with my DIY SIP Grow System.
My plants will be taken a bit longer because I want to see more fading lower down on them. A good flush really improves quality so a few more days is not a big deal. There are still some white hairs and that means growth is still going on. Waiting a few days at the end can mean more weight at harvest so no need to hurry things up.
I am seeing some purple in the Death Bubba and also the Black Banana. The Tropicanna can go really purple and she is. But I never got much on the Black Banana and this time some buds are really purple. Not sure if better watering is responsible or some other factor.
SIP GROW DAY 66 BEFORE HARVEST FINAL
Here is a video from day 66 and plants were harvested shortly thereafter. I had planned on taking things to day 70 because I wanted a bit more fade on the lower leaves. But the plants were ready and delay can lead to a decrease in quality.
Harvest Bud Shots
Everything turned out really well as you can see from the video below. Some buds were showing more purple coloration than previously. Not sure if even watering in my DIY SIP grow bed had anything to do with it or not.
All in all I would have to say my DIY SIP grow system worked very well. So I am going to continue using it. I did replace the small stones in one tote with larger ones and made sure it was level again. I have just started a new SIP grow in the same closet and you can follow that here: https://420grower.org/animal-cookies-in-new-sip-grow/