Just wondering what peoples humidity % they aim for in flower?. mines currently at 50% with a tiny dehumidy that makes little difference but does bring it down a wee bit during lights off.

What are your thoughts on optimising your environment and nutrition? When transitioning from HID to LED lighting, it is important to adjust the environmental parameters in your growing area to ensure peak plant performance. The Dio-Tech emits less heat energy than HID, this should be compensated by either, adding heat to the room, reducing the speed of the extraction fan using a fan speed controller or both. This is important to achieve the correct leaf surface temperature. If the leaf temperature falls below its ideal range and gets to cool it will affect the plants Phyto morphology and growth rate as it reduces nutrient uptake and its ability to absorb Co2 due to its inability to transpire. The ambient air temperature of each grow room will differ slightly but as a rule there is around a 4°C differential between a grow room, running with HPS (high pressure sodium) vs LED’S. As a rule, a room running with HPS aims to have an ambient air temperature of between 24-26°C this puts the leaf temperature between 29-31°C. When transitioning to LED’S, the ideal ‘lights on’ ambient air temperature needs to increase to between 28-30°C (or 30-32°C, if supplementing the area with CO2). These increases in ambient air temperature will in turn keep the leaf surface within the correct temperature range. Humidity can increase if the grower reduces the fan speed on their extraction unit to elevate their ambient temperature. To combat this the grower may need to install both de-humidifier and a humidifier with controllers to work in unison to maintain the ideal grow room humidity. The ideal humidity (RH) is 60-75% for vegetative growth and 50-60% for flowering. If temperatures are too cool, growth will be inhibited, and nutritional issues can occur. If humidity is too high the risk of fungal pathogen infection increases. High humidity and lower leaf temperatures reduce the rate of evapotranspiration (the flow of water from the roots, through the plant and out of the leaves) this also reduces the amount of nutrition entering the plant and negatively affects the mobility of calcium and magnesium, which will lead to deficiencies. If temperature and humidity are not optimal, adding Cal-Mag at a higher concentration to your usual growth schedule will help compensate for this. Vapor Pressure Deficit (VPD) is a measurement used to define how the temperature and relative humidity of a growing area effects the evapotranspiration rate of the plant. Using a VPD chart to set temperature and humidity parameters will significantly increase growth rates and yield. Digital Thermometer/Hygrometers are an essential piece of equipment for every grow room. A data-logging unit such as the Air Comfort will enable the grower to track environmental changes more accurately.

Hi Growmies I'm having a small panic about keeping my environment bang on and wanted to ask for your tuppeny bits! I've got 8 - 58L pots with healthy plants just at W4 flower - My temps are 27* and 20* and very stable - Im using the GAS enviro controller with the Revolution V2 8” - I’ve tried to drop my humidity to 50% using the GAS but it won’t seem to pull it down below 60% - I’ve checked all my settings and as it gets to 62-63 heater kicks in (dry air blower) and humidity rises… I’m a bit stumped! Could it be my outside tent humidity is just to high ? I’m using passive intake through two vents 400mmx300mm and have two clip fans blowing at them. I have good NAP on tent walls but not daft bowing - fan is set 30% min 70% max - if I go higher than that / worried it’ll suck itself into some sort of black hole implosion.. hope this is making perfect sense to someone ! Pd

Right as promised over in my grow diary here's a post about my Inkbird environment controllers. I have the IHC-200 WiFi humidity controller and the ITC-308 WiFi thermostat, I managed to get these for a steal at 50% off but full retail price these go for ~£100 which makes them significantly more affordable than many other environment controllers on the market. I'm using these devices to control my VPD and I have to say I'm extremely impressed. Both my temps and humidity have been extremely stable. Thanks to these devices not only are my temp and humidity perfectly stable, but both are being kept in the perfect range in relation to eachother, for optimal VPD. So a little bit about how these work. Each controller has a probe sensor and 2 power outlets, one for a device to increase humidity or temp and one for a device to decrease humidity or temp respectively, depending on what you have each controller set to they'll automatically switch between the increase/decrease devices to keep the temperature and humidity within the desired range. For example, for the humidity controller you could have a humidifier and additional extraction or a dehumidifier pugged in (or both with an extension.) When the humidity is too low it will run the humidifier until humidity hits the desired range then it will stop running the humidifier. If humidity starts to creep up it will run the additional extraction / dehumidifier until humidity is back where you want it. The same applies to the thermostat. Each device is only run when it is needed. There are basic versions of these controllers that don't have WiFi and for the budget conscious or non technical people they're potentially a good option, although don't think they'd offer the same level of precision when it comes to controlling your environment. But the WiFi version has an app that can be installed on a smartphone that's absolutely fantastic. The app itself allows you to remotely monitor and control both controllers independently from anywhere you have an internet connection. Which is a great feature in and of itself. However more importantly it has an automation feature that allows you to create rules for each device that can be triggered from the status of the other device or some other external factor. What follows is a short guide as to how I have these devices setup and how I created rules that will trigger and adjust each device as my environment shifts the devices will adapt to compensate, keeping my VPD in the ideal range constantly. Sensor placement. I placed my sensors at canopy level and far enough away from my heater and humidifier so that I'm getting an average reading rather than over indexing on any one reading. Obviously you know your grow space so make sure you're placing your probes in an appropriate location and that you're getting a good reading. The trickiest part of the setup was getting the devices to register on my WiFi but after a couple of attempts we were in business. To be fair the app does a brilliant job of guiding you through the process and it's pretty straightforward. Once they are connected and registered on your network you'll see each device listed in the app. From here you can manually set the desired value for each device. I personally use temperature to drive my humidity and set the temperature value to 24.5c and my temperature range pretty much fluctuates between 24-25c consistently. On the odd occasion I have seen it as high as 27 and as low as 22. But I haven't seen those extremes for weeks now, not since I was initially dialing in the setup. Now everything is dialed in though it's extremely stable indeed. Creating Automation Rules Ok so to create a rule firstly we select the smart option at the bottom of the screen. Next select the automation tab. On my screen you can see all my veg rules in green. Obviously the first time you see this screen it will be empty and rules will be added in the order you create them. To create a rule select the blue "+" icon in the top left. You'll then be presented with a screen that allows you to select what type of trigger condition you want to set. Because I want the devices to balance each other I chose the "when device changes status" option. My temperature like many of you, I'm guessing, tends to be far more stable than my humidity. So I opted to have my temperature value drive my humidity value. So on the next screen we select our thermostat. (ITC-308-WIFI) Here we're are presented with a list of options. I have used the "current temperature" parameter. Each rule I have created is set at 1c increments. I also use the "<" (less than) condition I originally set this to "=" but as soon as the temp shifted by 0.1c the rule would cease to apply so using "less than" at 1c increments covers the entire range of decimals. Select the upper limit of the temp range you want to cover. On the next screen we need to select what we want to happen when those conditions are met. In this instance we want to run our humidity controller so select "run device" Now select the humidity controller (IHC-200-WIFI) Next we want to select what we want the humidity setting to be, so select the "Setting Humidity" option. Use the slider to get in the right range if you want to be really precise you can use the + and - icons to make fine adjustments. Here you'll want to refer to a VPD chart to select a humidity value that's appropriate for the temperature threshold you have selected for this particular rule. The rule we are creating is for flower so I have used the appropriate settings assuming a -1c leaf temp offset, these values will give us a RH of 51% between 24-25c On the last screen you get a summary to review before saving and activating the rule. So for this example we are using <25c as our threshold temp. So to recap what we have said to the app is "if the current temp on our thermostat is <25c then set our humidity to 51%" now where this gets really interesting is that you can stack the rules up so if I set a <26c rule for 53% humidity we have now told the app 2 things: "if the current temp on our thermostat is <26c then set our humidity to 53%, unless the current temperature on our thermostat is <25c then set our humidity to 51%" You can then add additional rules for <24c etc etc and you continue to stack these rules one on top of the other until you cover your entire temp range and a couple of c either side just in case. There's a whole heap of other options I'm yet to explore with this but just this functionality alone for the price is pretty fantastic. Yes there's quite a bit of setup involved but once it's done and your rules are saved you never have to look at it again other than activating or deactivating the rules for the various growth stages. At the moment I only have a complete set of rules for veg setup. By the time I flip I will have created a full set of new rules for optimal flower VPD. You can colour code the rules so you can easily see at a glance which rules are for which stage my and you can activate and deactivate any given rule using a toggle. So when I need to, I can just switch between different rule sets easily and there's no need to recreate rules from scratch all the time. If people find this post useful I might explore some of the other features in the app and make additional posts over time. Keep it green -NezA

Hey, If I’m saving to invest in the best possible extraction set up I can afford is the controller a important part of this set up? Been looking mostly at EC fans,filters and ducting but is the controller a big player in the environment foundations

Hi yeall I have 2 different digital temp and humidify readers in the 2x2x5 and I have a humidity reading of 50% approx which is good for flower. To get this to 70% in such a small tent I was thinking the "RAM 5 Litre Tank Ultrasonic Humidifier" would be overkill. If you have any tips on how to get my humidity up 20% please tell as I was gonna hang a wet towel in there but dont want that near electrics. Cheers.

Hi yeall I have 2 different digital temp and humidify readers in the 2x2x5 and I have a humidity reading of 50% approx which is good for flower. To get this to 70% in such a small tent I was thinking the "RAM 5 Litre Tank Ultrasonic Humidifier" would be overkill. If you have any tips on how to get my humidity up 20% please tell as I was gonna hang a wet towel in there but dont want that near electrics. Cheers.

Hi everyone Before I spend a few quid I thought I would just pass this by yeall just in case. I have the VIPARSPECTRA P1000 ordered with a small 45 watt green house bar heater this will be plugged into an "Inkbird ITC308Wifi Thermostat" to regulate the heat .To cool the tent down the "AC INFINITY CLOUDLINE S4 EC FAN 4 INCH". To control humidity use a "Inkbird IHC-200" with a dehumidifier & humidifier attached. My question is this, is this an overkill set up for a small tent? as I also read that you should have the exhaust fan on 24/7 but with the Inkbird it will go on then off due to the temp inside the tent....this is were its grey to me. Any tips welcome. Thanks.

Got 5 plants (2 autos and 3 photos) in a 1m2 tent (ambitious I know, but the 2 autos are nearly finished and will then leave plenty of room for the photos which are only two weeks into flower). I run a big 10L Meaco dehum in the room, because I'm venting into the same room, and a small 500ml ProBreeze in the tent itself. I'm averaging 55% RH in the room and about 60% in the tent, which is a bit higher than I'd like with my autos chunking up so much. My question is whether anyone has any experiencing running a big dehumidifer in the tent and whether it caused any problems to be aware of please?

In a 1m x 1m x 2.2m, got 5 plants going (I know, pushing it, but two autos and 3 photos, with the aim that the autos will be done and out of there around week 2 of flower for the photos). Using a telos 10, got two circ fans and my 5" rvk running on setting 3 or 4. My humidity has recently jumped from average 60% to now 80%. I have a ProBreeze 500ml dehum but it doesn't seem to make much difference at all. I know I'm lacking a heating element in the tent so have been looking into options but don't have any floor space spare, so am looking at either having a radiator near the intake or a tube heater in the tent. Does anybody have any opinions please on whether either of these options will help with my RH problem? Many thanks in advance

So I have set my grow room up and everything is running nicely, temperature is stable and constant at 25c. While doing a dry run before I plant my soaking seeds, I have come to run the humidifier to bring it up to around 65 for seedlings. However I cannot seem to get the room up from 55, I have a decent humidifier it is the levoit lv600hh, I have set the humidity to 70 to bring it up, it's on max mist output. For the size of the grow space this humidifier is and should be more than capable to work as required. Has anybody got any advice, thanks

So I'm about to begin a grow and I'm just currently running the grow room to see how everything is working. The fans I have bought to use as the intake and extraction seem to be quite powerful, and the grow space is the size of a tall fridge. I'm having trouble getting the humidity to rise, I have the temp at currently 25c. Is there any way of reducing fan speed or the amount of air that's being drawn and extracted. As the fans I have do not have any control options . I feel like before the space even has time to adjust its being replaced with new air and the humidity is very low.

Ok, sick of budrot, especially in winter in the U.K., caused by high humidity. I invested in some sensorpush Bluetooth monitors to see a continuous record of temp and the and a ram 10lt dehumidifier and I’ve been experimenting with placement. And recorded changes via sensors. from everyone’s experience where is best to put dehumidifier? in tent? Or outside tent near intake? If in tent is it best in middle of space or near intake etc? just to say temps are fine. Got smscom 4a hybrid doing fans, a lighthouse WiFi plug doing two tube heaters. It’s just the high humidity at this time of year particularly at lights out.

Hey all hope you are doing well, on my first grow and about 6 weeks in now and getting way to high humidity readings in the greenhouse over night. Just wondered if any of you had any cheap ways to control humidity? Obviously there is the option of ventilation, heating and a dehumidifier but some of these options can be pretty costly. Have any of you ever used products such a moisture absorbers? Will an everyday bedroom humidifier work well in a greenhouse?

Hi there ran into some issues maintaining humidity in seedlings grow area. temporarily maintaining humidity with a ziplock bag ofer the pot, but this cant be ideal as the seedling as no fresh air. For young seedlings would you prioritise humidity or air circulation? normal humidtiy without ziplock bag is 40-45% Thanks S

I'm planning 3mx3m space w/ 6x 600's to use end of flower. Air extraction 1080-1350m3/hr (depending on which fan I get) intake 800m3/hr. Inside target climate: 25-30°c RH 65-80% Avg outside climate: -2-10°c RH 60-90% Never used inline, kept running into low humidity this time want inline+humidifier. I played w/ online humidifier size calculator it said I need around 14-20kg/hr=14-20l/hr to keep up with extraction. Long story short seems like this is industrial size and way out my budget so instead wondering anyone knows how to make a humidifier maybe w/ pond foggers/mist makers+centi fan? I'm all ears to any advice, thank you in advance:)

Want to run a humidifier+dehumidifier in my tent where each activates only when needed using inkbird controller, my goal is to maintain RH 75%-85%. Q's: 1. If I were to use humidifier/dehumidifier where would be the best place to install them? Close to intake maybe? 2. Is it pointless to run these when your extracting air 24/7? 3. Is there a way to calculate humidifier size? P.S. I KNOW HIGH RH AND CARBON FILTER DOESN'T MIX PLEASE LEAVE THAT TO ME

Formula I've come across: Maximum amount of water you will ever give your plants(probably flush period) x the amount of plants. Problem is how the heck would could I possibly calculate how much water I'll be giving my plants?

Hi Does anybody use Inkbird products? Im looking on eBay at a Inkbird temp socket....It has 2 sockets on it and wonder if one can be used for a heater and the other be used for extract/cooling Its also the same with the humidity ....I guess plug a humidifier in one socket and a dehumidifier in the other any advise would be great Thanks in advance

Hi Guys First time grower looking for advice please. I’m planning on putting a 120x120x180 loft tent in a loft, the loft has Humidity levels of RH 80-95% depending on the temperature. Now I know the humidity being this high is a problem but would I be right in thinking, that if I intake air from a bedroom below ,with humidity around 50%, directly into the tent, that this would keep RH in the tent at a more suitable level? has anyone else had this issue or does anybody have any solutions? thanks in advance

Please move if posted in wrong place Hi everyone. Been reading on here for a while found a lot of helpful information that’s helped me with my first few attempts. Long story short I started growing to help my mum who had terminal cancer with pain relief, fast forward 18 months and I’m now on my 4th grow. I’m struggling to achieve gpw and think this is down to my environment. I have a 1.2m bloomroom loft tent. I have a 6 inch outtake with a rhino filter. Currently using passive intake with a bit of ducting from room below. Running a 600w hps with dimmable omega ballast. X2 oscillating fans, humidifier for veg. 700w oil filled rad for lights off. My fan is a rhino thermostatic but I don’t think the temp control is very reliable. I’ve been using 11l pots with pure canna coco. Using canna range a and b, rhiz, cannazym, boost and pk. Swapped pk for bloombastic on current grow as advised by someone better than me lol. Watering every 2 days up to 2.5L in flower! Don’t seem to be getting the growth I would like in veg and seems to take forever for them to gain size! Now for the questions please! Do I need an intake fan? If so what size? Recommendations on fan controllers for intake outake and heater? Or easiest way to control them all? Would I be better doing 9x6.5l? Less veg time? If so would I put them straight under hps from cutting? A lot more info to share with you guys if you need any to help me! Sorry to ask so many questions on my first post! Thanks in advance

Evening everyone, Sat, chilling wondering something.... What's everyone's thoughts on the best way to control humidity during flowering, without spending loads on a DE-humidifier? What is your preference and why? I have a small £20/30 one it's electric combined with two calcium moisture catchers..... 60-75% humidity still... It's a small grow tent, with two flowering and 3 germinating. (I appreciate its cramped) Left the tent slightly adjar etc, which is how i achieve 60%... Whats the chances of BUD rot as we stand... 50/50?? :/ Thanks