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.

8) 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 :-P

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 :shock:

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.




Well-Known Member
Ok, forget all that shit I said :-?

In my current grow, the only plant that has really been doing well with the Blumats has been the sativa snow goddess. So I started thinking about that.... one thing that stands out is that it waters differently..... it goes along with no drips, then it quickly ramps up to a steady stream of drips and continues through about a gallon of water, then they shut down. This is how they are supposed to work, so that the top couple of inches of soil can dry out to an extent.

I recalled that early in the grow, I was having issues with this plant. So I started fiddling with the blumat setting back then. And as is the risk when you fiddle with shit, I started a run out. However, I caught it when the water level was about 1/2 full in the drain tray. I figured that the soil and ceramics should be good and sopping wet, so I calibrated the Blumats per the directions except I only closed the valve 1.5 arrows. Ever since then it's been throwin down. The other plants were calibrated in the method I described in the original post. So I'm pretty sure I've been under watering. I just re-calibrated the other two plants to match, I'll report back if I've actually got it figured out this time lol


Active Member
Bubba thanks for sharing your experience and expertise with blumats it will make my transition much smoother. You rock man.


Well-Known Member
My pleasure. I researched extensively and found some decent info, but nothing that brought it all together back when I started with them. Hopefully folks googling 'Blumats' will get a link to ole Bubba's primer now.
Nice info Bubba. I have been using Blumats for outdoor plants for four years. I use a 55 gal. res for watering outdoor potted planters and beds. The reservoir is a rain barrel that sits up on my deck that gives me about 5 feet of head.
I wanted to use Blumats indoors in the grow room but I just don't have the setup for it so I hand water my indoor plants. I found that they take a little practice to get the hang of but it really saves your ass when you have to leave town for a few days.