Best Place To Measure Growroom Temp

Where is the best place to measure growroom temperature when lights are on?At the tops of the plant or at the bottom of the plant?There seems to be a 15-20 degree difference in temp between the two.Like 90f at the tops and 72f at the bottom.

 

Between top and lights

 

Good Ganja there's an 18 degree temp diff. between the top and bottom of the plant?
How tall is that sucka?

 

Do you have a fan circulating air

 

Best way:
an infrared thermometor measures the actual temp of the plant .
so point it at that part (top, tip of branch, etc.) that is closest to the light.

Remember_ the temp of the plant is not simply a reflection of room temp when the room contains a light/heat source. The plant itself absorbs radiation which add aditional heat to the veg material.

If you're already using an infrared (sounds like you might be) a large discrepency between top and bottom is not unusual.

as for room temp discrepencies- a little circulation goes along way.

 

Thanks for the input guys.There is an osculating fan in there but the problems comes from the intake fan being ducted on the floor.The cold air is down on the bottom thus keeping the temp down there colder.Is it best to duct the intake vent up to the light?The osculating fan is mixing it up good but I was concerned that the temp at the bottom of the plants would stall its growth.If the roots are colder does that effect plant growth?Do you guys keep your outake fan vented on the ceiling of the growroom or duct it down by the lamp height?This one is ducted down.I know I have a lot of questions so any help is appreciated.By the way that sucka is only 3' tall.

 

I dont know what size light ya run but these are 600 hps air cooled thru carbon filter into crawl space.Ambient room temps with co2 generator never exceeds 75 degrees and at canopy highth it never exceeds 78.Without generator going subtract 3-5 degrees.Optimum temps at any point of origin should be maintained between 72-78 depending on strain for best benefits .There is a 16" oscilatting fan but it has "0" effect on temps,merely keeps C02 enriched air moving throughout the foliage while between C02 cycles.

 

for a stop-gap, add a small additioal fan and aim it at the light itself to aid in disapating the heat build up around the bulb. Don't worry about blowing the plant around a little.

If you do not more-or-less equalize the air temp in all parts of the room, your yield will be drastically reduced, and your flowering time may suffer.