What is the ideal light level as measured by a meter for indoors?

I have a meter now and need to know the ideal intensity of light

I know that the bare minimums are one thing, but the max can be way too much. There must be a median “IDEAL” range that is best for indoor growing, what is it?

What I read right now is an average of 500, but the plants seem to like it

What do you get in direct sunlight? Shade? Those values might be, wait for it, illuminating hahaha!

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500 what? Look for about 400 umols on a par meter for veg, and 800 or so umols for flowering. Again, that takes a par meter, those numbers are not lux, lumens, or foot candles.


Regarding the phase your plants will be, they will support better different µmols, but the light intensity check is important in order to give the maximum amount of lumens without burning your plant. I don’t use such meter, so I would say that a lamp of 600w should be between 60 and 80cm.

I’ll follow the coming answers because I wanted to acquire a light meter soon !

I just did a montage of the setup and controls I have now - I think a lot of you are going to like my “Bath Tub Factory”.

Top left is a timer for my lights, I have a 1200W equivalent full par spectrum LED fixture, and a pair of LED Spotlights that will soon be replaced with 1520 lumen white LED “Bright Sticks” and I am looking over a couple of RED LED light “bulbs” to go in there also, timer is set to 18 hours now. I got tired of trying to be up at 6 to turn on the lights (and missing the timing on several occasions) and also staying up until midnight to turn them off.

Second from top on the left I have a three-way plant meter of the general kind for Light, PH, and Soil Moisture checking, and next to it is the Humidity Control for the Honeywell humidifier I have on a small shelf I made to go over the angled up end of the tub. Next to the humidifier is a small fan that is turned on by the controller at the same time so that the mist is well spread out in the enclosure.

I set humidity to 52.5%, and you can also see a thermometer at the opposite end in one of the buckets.

~ As you can see, except for watering, feeding, and measuring with the 3-way meter it’s completely automated now…

That last yellow bucket has the first and only sprout so far of Durban P. in it, the others are Jack Herer (FEM’d) so I think of them as Group-1 and Group-2

Now, this IS a first time grow. But I think I almost have it down at this point. The soil responsible for the deviations in the Group-1 plants has been identified and corrected.

Each of the Group-1 plants are in the middle of week six

ANYWAY, that being a standard meter - does it mean that it reads in umols?