blumats cannabis

Blumats – Bubba’s Lessons Learned

Well-Known Member

Some of y’all expressed interest in learning about using Blumats to set up your garden for auto-watering. For those not familiar with Blumats, they utilize a ceramic actuated valve. when the ceramic drys up, the valve opens, then once the ground is wet again, the ceramic soaks the water back up, swells, and shuts off the valve. basically. Read the official directions before reading the following as it will probably make more sense.

This is not the correct forum to post this. but this is where I hang out.

General Tips on dem Blumats

1) I wouldn’t use a blumat in a container 1 gallon or smaller. I have done this and the plant got root bound inside of 3 weeks. probably due to getting the on-demand water, though they were also setting on a heating mat.( See pic )

2) Plumb in all Blumats before the grow, even futures that you won’t be using at present, I just shut the blumat valve fully, wrap the capillary tubing up around the blumat, and leave them hanging from the feed line in the tent. You will have to soak them in water before use, but that can be done in a pitcher of water set in the tent.

3) My reservoir is approx. 4′ above the dropper level, but the blumats will work with lower head pressure. This info can be found in the Blumat literature I’m pretty sure.

4) Bleed the air from the system at set-up. Best way to do this is with the ole mark one human suction system (I.e. make like you’re jacking someone’s gasoline and suck the air out from the end of the line, then from each branch capillary tube. If air is left in the lines, it can cause a run out of the whole reservoir.

5) Never let the reservoir run dry. If you do, bleed the air as in #4 or bad things will follow. Of course you also now have to reset the Blumats. How I do this is by leaving the blumats in the container so as not to disturb the root growth around the ceramic probe and thoroughly wetting the soil. Then I wait 30 minutes or so to make sure the ceramics are soaked. Then I open the valve until water is dripping freely, then slowly close it until a drop will form, but won’t fall, then I continue to close the valve 1 to 1.5 marking arrows. The blumat directions calls for turning the knob 2 arrows after you form the drip that won’t drop. I attribute the difference between the official directions and my preferred setting is due to altitude, but I have no evidence to support that other than the plants seem to need more water than what the directions calls for.

6) Never turn the adjustment dial more than 1/2 of an arrow once per day. Small movements or bad things may follow. The only exception to this rule is when trying to get the two blumats in a common container balanced. You have to keep an eye on things and when one blumat starts watering, then you adjust the other blumat to get the same # of seconds between drops. If you know that you will be around and will look in on things, then you can move more than 1/2 arrow, but I wouldn’t go farther than 1 arrow per day in any case.

7) I only run clean water through the blumats. Feedings are done by hand as I fear the nutrients plating out on the inside diameter of the capillary tubing and causing restrictions or blockages. Having said that, I plan to experiment in the near future with including Dyna-Gro nutes and pro-tekt into the reservoir. That just seems like the next logical stop on the quest to max my grams/watt.

Blumats deliver the optimum moisture level to the roots (when properly dialed in). Unfortunately, this doesn’t ever give the flushing action of heavy hand waterings (btw you should never see standing water in your drain trays. except after hand feeding). I have come to the conclusion that you should flush the container with water in the amount of approx. 3x the volume of soil at least a couple of times during the grow. After each flush, I take the opportunity of a fully soaked medium and blumat to reset the blumat valves as I believe that as a plant’s demands change through growth, then the blumat setting needs to change also. An engineer would probably explain it like this: the water demand curve described by the growth of cannabis from it’s juvenile state to a fully mature state is not a linear (i.e. 1:1) progression and therefore requires that the Blumats be adjusted from time to time to compensate for the divergence between the linear and actual paths. But then nobody likes to hear a propeller head drone on

9) I recommend redundant Blumats in each container if you’re away from home much. I put two maxi blumats in each 5 gallon pot. Each blumat has two T droppers and one 90 dropper. I position two droppers on one side of the stalk and the last on the other side. same with the other blumat. Probably overkill.

10) You don’t have to use a dropper if you are just going to have one drip – you can just let it drip from the end of the capillary tube. For multiple drips, I suggest that you use the store bought blumat droppers.

11) Max reservoir size depends on your stomach for cleaning up runoff (which you shouldn’t have if you follow these directions, but no guarantees). I would think twice before using the pressure reducer thingy that Tropf makes. It allows you to tap house water pressure and it steps down the pressure to something more appropriate for the blumat system. but if you have a run out. it will not stop until the city or the well runs out of water

12) I utilize a 2 reservoir system to balance the need for sufficient capacity on hand against limiting possible run-out clean-up. The upper reservoir is 10g and preferably clear or white so you can see the water level (mine came from Murdock’s and and is black, but it has a home grown sight level gauge installed). I keep a 5g bucket full of water at ground level with a Rio 2100 pump (old saltwater aquarium circ pump) in it connected to a hose to lift water to the upper reservoir. I manage the hose at the upper reservoir lip interface by using a dishwasher drain line thingy originally purposed for running a dishwasher drain line into the PVC riser under the sink. This keeps the tubing from forming a kink and allows for easy securing of the hose to the lip of the reservoir. you don’t want to have shit floppin around when you plug in the pump unless you need a shower.

14) A good sized Sativa will suck down 1 to 2 gallons per day. So if you have 3 plants, you gonna go through 4-6 gallons a day at the height of flower. This is an issue with my res only being 10 gallons. My solution is that I have my lovely wife go down to my grow room while I’m gone. if she can’t see the water level in the gauge, she pumps up the 5 gallons in the bucket by just plugging in the rio pump until it starts sucking air, then unplugging it. This has been enough to get me through 3 day travel trips. for five days, she would have to add the 5 pitchers of water I also leave out just in case.

15) I keep a small pump in the reservoir to keep the water stirred up. You could probably aerate also if you wanted. but I’d be paranoid about getting air in the lines. I’m really not sure if the pump in the res does anything, but it don’t hurt nothin either.

16) Air bleed line – I’m not sure if it helps in keeping air out of the lines, but I put a T in the feed line just downstream of the reservoir and upstream of the shut-off valve and run a short section of tubing vertically from the T so that the end is 6″ or so above the water level in the reservoir.

Shopping List: (Way to Grow has most all this stuff)
– Blumat Maxi or original Blumat (the original sized blumats are for pretty small pots, I bought these for keeping my forthcoming bonsai mothers)

– Feed tubing ( I forget the size, but it’s fucking metric, about 1/4″ID if I remember right)

– Feed tubing fittings: splices, 90s, Ts, bulkhead fitting & shutoff valve
– Blumat tubing (small diameter metric tubing. maybe 1/16″ ID) – you need plenty of this so that you can replace the short section of tubing that comes with the blumat. this gives you enough slack so that you can turn the pot 360* and move it around to an extent without having to disturb the blumats.
– Feed tubing to blumat tubing fittings: 90s & Ts
– Droppers: 90s & Ts (the assortment package comes with a roll of capillary tubing and assorted droppers and is a pretty good deal, but it has too few 90* droppers IMO)
– Dropper stakes – I use regular drip tubing stakes – one for each dropper

A) Thoroughly wet the soil. I soak the soil the night before while the blumat is soaking in a pitcher of water. Then, the next morning I make sure that I have the dirt good and wet by giving it another medium sized drink. And yes, the plant will droop if its already planted from this abundance of water but it will be fine. I do usually evacuate the water left in the drain tray to give the plant a head start on respirating that excess water off. (I use a small pump in the drain tray to get most of the water – I also do this when flushing since my plants are in a Scrog (last time for that bullshit I can tell you).

B) Place the pre-soaked Blumats opposite each other with the stalk between and keeping each a little closer to the container wall than the stalk. Be sure to keep at least an inch of packed soil between the blumat and the wall of the container.

C) Insert the blumat into the soil, but leave at least 1/2″ of the column plus the cap above the soil. I only do feedings by hand and care must be taken so as to not feed to the point that the water in the pot goes over the cap because grit can get in the valve and can cause either a run out, or worse, it sticks and doesn’t water at all. (I think this is what happened to the poor Z7 that I parched to death while out of town)

D) Follow the Blumat directions for setting them initially. but like I say above, I only go 1 to 1.5 arrows after getting the drip that won’t drop. I typically only ever adjust the blumat valves towards the closed position is if there is water standing in the drain tray.

You’ll love to hate these things. When dialed in they are a thing of beauty. But even when they aren’t optimized, they should keep your plant alive while away.

Some of y'all expressed interest in learning about using Blumats to set up your garden for auto-watering. For those not familiar with Blumats, they utilize…

Blumats and coco


I have been searching for a digital drip feed systems to help improve yields in coco, currently hand watering 100% coco first grow. I came across blumats and have been reading the past few days and have a few questions.

In the cabinet there are 2 x 4 gallon pots. Should I use 1 blumat with a feed/dropper line to ensure it is fed equally or 2 blumats (incase of clog) per pot? I understand using 2 blumats takes a little longer to dial in.

Should I be using blumat or blumat maxis? what are the benefits if any of each?

I have read blumats can clog up in use. Which part of blue mats are prone to clogging? Is it the feed line which will clog or the actual ceramic which clogs (perhaps with salt build up) which may cause them to constantly water? This worries me as I do not want to flood the cab. I plan on feeding with nutes (not just water) which some don’t recommend. Most likely with a 500-700ppm. Previously hand fed once per day around 1200-1300ppm.

I grow vert scrog so can’t move my pots. Is there and precautions I can take to prevent a flood other than drip trays. I am concerned they may spoil my days if they were to flood and overflow my drop trays.

Anyway thanks if you can help with this, I am new here but blumats are more discussed here than the other forums I usually use. I am starting to warm with the idea of blumats over a digital timer and pump.


Blumats are awesome, but kind of superfluous in coco.

You know exactly when and how much water they need from hand watering all the time.

You can set up a drip manifold on a pump and timer for a fraction of the price of blumats. And nutes will be fed easier with this method.

Blumats are for more practical for super soil water only type of drip system. IMO.


The pots I am using are 1 foot deep. The way I see it is that std blumats that sit at the top would simply feed more often as the top of the coco will dry first. Where the maxis would feed a little less often. Ultimately I suppose if you adjusted the maxi you could compensate for it either way. I guess which ever one will leave me with less runoff but as I can not make up my mind so hoping someone could simply tell me and provide me a reasons I haven’t considered. Also, if it is only the feed lines I have have to worry about clogging if I use 2 blumats clogging won’t concern me as much. I only need to set up a few pots so I am not concerned if it takes a long time to set up]

As I am strictly limited to 2 plants in the cab maximising yield is critical for me, however to my advantage I can veg as long as required. By hand would be fine however I do not have the time to ensure 3-5 regular feeds per day during veg and flowering, as when I add clay pebbles to the mix I know I will have to feed regular and often to compensate. I feel blumats would allow the plants to feed themselves better than a timer as they essentially have feed on demand but do not know if this is a good enough basis to choose blumat over digital timers. I think blumats may help reduce runoff. But clogging scares me. Other posts reported explosive growth and increased yields from using 25-40% clay pebbles and multiple feedings at lower ppm . I have noticed from hand watering once per day with 100% coco my root ball was not very impressive even with 8-9 weeks veg, although this was my first grow I hope the pebbles will help with this.

For gravity feeding I can sit the reservoirs on top of the cabinets so 5-6ft above the pots, plenty of potential energy down the tubes, will this help prevent any clogs? The nutes I am using are all liquids, the full canna coco range with a calmag feeding 5.6-5.8.

If cost is not an issue what do you feel would be the best option based on: Regular feedings at intervals during the day (timers), or letting the plants drink as much as they please (blumat). And opinions on which would be the most reliable?]


The problem I ran into with blumats in a soilless medium is keeping the Rez PH’d to 6. Even with a top off Rez it needed constant monitoring since they are more sensitive to PH in a medium like coco and you never really know who is drinking what at what rate.

With pumps and timers you know exactly how much water/solution is used everyday. You’ll be able to dial it in perfectly for your exact useage and no worries running nutes and drip clean thru it.

I’ve never had a blumat fail but I’ve had a few runaways. And that can be a pain.

The drip manifold will be as reliable as your pump, timer and how well you set it up.


My reservoir is four feet from the floor. The line runs through a wall, across a 4ft tray, another 2ft of space, then another 4ft tray. Blumat spec says you only need 1:10 slope but that seems too gentle. My clog occurred in a pot in the middle of the first tray. Lack of pressure was not the problem. I opened the brown cap pinch valve all the way and no flow. It flowed when I squeezed the 3mm line right next to the 8-3-8mm elbow. I don’t know what was in there.

Other than the plant I neglected (I saw it start yellowing but I assumed it was from over saturating the crappy old Atami coco I used), things ran as expected. The yellowing was from starvation–the pot was feather light when I picked it up. Things got overgrown and my back was used up building the flower area but slightly lifting each pot tells you if the weight is good. I started out too dry, the greenest, healthiest plants had the most saturated coco.

I just culled a male. Some people don’t like Blumats because they don’t make full use of the pot. Maybe a third, the third furthest away from the dripping won’t have dense rooting. I haven’t had the time to dump the pot and check for sure.

I really haven’t had problems with pH drift. Maybe once or twice a week I throw in an extra ml or two of GH pH Down. I’ve only handwatered dirt before so I really don’t know what I’m doing.

You’ll have to check sunnydog’s Blumat thread at IC for what pot depth works best with the Maxi version. As I recall, a four gallon pot one foot high would call for a pair of reg Blumats.


(Resurrected plant in middle front.)


Thanks for the responses. I was almost sold on digital timers but the more I look at them the more possible complications appear and having the high reservoir with blumats is more practical for the space I have, although I may have to invest in a step ladder. That said if I had more than 2 pots I would probably go the timer route. The only disadvantage with the blumats is you miss out on multiple wet dry cycles in a day, I am hoping the clay pebbles will make up for this.

I will order all the little bits needed the next few days and check back when I have it together. That said I don’t really think I look forward to setting the thing up.


I used a 3.5 gallon bucket filled with water when I assembled the cones. I love the plastic pipettes. Soak the ceramics over night. Don’t store an assembled Blumat in water, though, someone said they swelled over time and cracked the cap. Be sure to pull the feeder hose at least part way through the cap when brand new–a kink forms there.

The 3mm feed tube should be extended 8cm from the cap, according to Blumat. Some people adjust drip rate by playing with this length but I haven’t tried that.

I think my intermittent runoff is caused by cold lights-out temperature. It’s about 66F in my basement.
From the operating instructions:
Always leave the water tap turned
on or replenish the water tank in
good time. Even when it is raining.
With longer interruptions to the water
supply, the roots can suck the water
out of the sensor. Don’t be fooled by
a dry ground surface. The water
spreads underground like an onion.
Often only the ground surface under
the dripper hose is visibly moist.
» TIPS when going on
• Install the system at least 10 days
before. • Support the plants from
falling down and do not place in
subsoil susceptible to damp.
• Eventual water leaks must also
not cause any other damage (e. g.
flow into cellars or the like)

Tropf-Blumat does not
turn off?
Membrane has too little tension
(can occur after cold nights).
Close the setting screw
approx. 1/2 mark.
No water comes out of
the dripper hose?
Hose is blocked, stuck or
supply buckled.
Withdraw the dripper hose a little
and knead the compressed part
between the fingers.
The sensor runs out of
Air has entered the system,
poorly screwed together, buckled
dripper hose, poor ground
contact, interrupted water supply.
Refill the ceramic sensor with
water and screw together
tightly up to the marking ring.
The watering diameter is
too small?
Dripper hose is too short.
The water therefore reaches the
ceramic sensor too quickly.
Extend dripper hose to 8 cm.

Hello, I have been searching for a digital drip feed systems to help improve yields in coco, currently hand watering 100% coco first grow. I came across…