The Grow Sensor and VPD

When it comes to growing the best plants indoors, there are many areas to focus on.

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• Genetics 
• Environment 
• And plant inputs

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To name only a few!

Many growers jump straight to the inputs as their primary focus to improve yield and quality, for example, nutrients. I mean, you are what you eat, right? 

But generally, you can’t perform your best if your environment is poor, and it’s the same for plants. 

The best growers put their environment at the top of the list, and I do the same.

Creating a truly controllable, repeatable environment year-round is not easy, and it’s a vast topic.

A grow room is a constantly changing environment. Your plants have different needs at different stages of growth. And the environment where you live most likely changes throughout the year. 

This means there are many constantly changing variables which can make repeatable results hard to achieve. 

This week, we are learning more about 1 key part of managing your grow environment. Vapor pressure deficit or VPD for short.

Optimal VPD levels create a favourable balance between transpiration and nutrient absorption. When VPD is too high, the air is dry.

This causes excessive water loss through transpiration and can stress the plants. Stressed plants can suffer from wilting and nutrient deficiencies.

Conversely, when VPD is too low, indicating high humidity, transpiration decreases, potentially causing stagnant growth and increased susceptibility to diseases.

If you can master your VPD, you can master an essential part of creating the best environment for your plants. 

If you can hit your VPD target you’ll notice a substantial increase in quality and yield, just like that.

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Is VPD bro-science?

VPD isn’t new in the growing industry. It’s been known in one form or another since the 1920’s. 

As time has gone by and with the revolution of indoor and greenhouse growing, it has been refined into what we know today. 

Cannabis growers then took this and applied it to their own situations. 

But does it work? Is it bro science? And how important is it really? How can I start dialling in my VPD?

There is extensive and well-documented scientific literature proving the importance of VPD for plant health and yield. So yup, it works for sure! And no, it's not bro science. 

It is extremely important for your grow, but there is a caveat to this. 

VPD charts tend to give us a safe band to follow (ours does, too). Every plant will have an absolutely perfect VPD to aim for because every plant/pheno is different. Dialling that in makes a huge difference at scale, but with smaller grows, it’s harder to observe the results. 

Don’t get me wrong; the same thinking applies to every grow, and you should be dialling in your VPD as closely as you can, but you can grow good plants within a wider band than most will have you think. 

But as we are always on the hunt to Grow The Best dialling in your VPD should be top of your list and is a great place to improve. 

Put your environment first!

If you're not dialling in your VPD yet, you should see some pretty big improvements within 2 weeks of doing so.

So start off by getting your plants in the correct VPD zone for their phase of growth. As long as you’re hitting the right temperatures, you will see fast, lush, healthy growth.

• Check out our VPD chart and timeline to get the VPD for your complete grow here. 
• Here’s a great study showing the difference a dialled-in VPD can make.
• To learn more about dialling in your VPD check out this post here. 

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Does the Grow Sensor measure VPD?

Yup! It measures it 24/7, giving you a complete overview of that metric in your grow. 

Our app shows VPD data as a live graph for both night and day. 

You can also set alerts for both photoperiods, giving you total control over when your lights are on and lights are off.

You can set limits on your data too, meaning you can set a high and low limit and a dangerously high and low limit on your VPD (as well as other metrics). 

This doesn't just apply to VPD but everything the Grow Sensor measures. 

When you set a high or low limit on your graph, it appears as a purple line, so its super clear how close you are to your limit.

The great thing about the limits is that when you change them in the Grow Sensor app, they change from the time you set them onwards.

This means you can see how you changed your limits historically from seed to harvest when you look over your complete grow.

This is game-changing as it clearly shows you how successful you were at keeping to your limits. 

And, if the results were good, it makes it easy for you to repeat this next time. 

In the near future, we’ll release custom templates that set up the limits based on your stage of growth and your goal. E.g. veg, flower, quality, yield, and power saving. 

All of the above makes managing your VPD clear and concise, and it is all from your mobile. 

Got a question about this feature? Hit reply and drop me a quick message.

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Happy growing!

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