My Failing Winter Greenhouse Sniff Sniff...failure.

[pic book]

actually, what i built is a hoophouse with 1 1/2" pvc pipes overlaid with 2 layers of 3-mil clear construction plastic, over a heating pad buried 17 inches deep to warm the root zone.  heat rises, right?

(the 20' x 20' rubber pad encases wires--like a temp controlled seedlings  pad).  The pad is intended by the mnfr to warm basement floors or any level surface that needs have its temperature increased.   Burying the rubber pad was my next idea, after laying it under a row of planter boxes failed to warm them up.  (The air gap of 12" chilled the air beyond the pad's ability to warm the soil). 

 

my first crop of buds is small, and some of the buds that touched the plastic are burnt and useless.

 

i am irritated.  for one thing, i bowed the pvc from the ground on one side to the ground on the other side.  Next time I'll build tall sidewalls at least 6', so i don't bump my head, and have space to work all around the plants.

 

and of course, the small buds say that the heating pad is buried too deep.  at the soil surface the temp always read 48f or above, yet it may be that the roots suffered a loss of efficiency from being so chilly.  (and the roots didn't go more than 6 inches deep).

 

additionally, as tho i don't have enuf probs already, the sun's light may be too weak to raise normal size buds.

 

possible fixes:  supplementl hps.  

and dig up the heating pad and in its place, bury plastic water lines under the hoophouse and pump hot water through them. and maybe, to warm the air in the hhouse lay some warm water lines on the surface to warm up the ambient air from 60f ti 75f?

[Highlander]

actually, what i built is a hoophouse with 1 1/2" pvc pipes overlaid with 2 layers of 3-mil clear construction plastic, over a heating pad buried 17 inches deep to warm the root zone.  heat rises, right?

(the 20' x 20' rubber pad encases wires--like a temp controlled seedlings  pad).  The pad is intended by the mnfr to warm basement floors or any level surface that needs have its temperature increased.   Burying the rubber pad was my next idea, after laying it under a row of planter boxes failed to warm them up.  (The air gap of 12" chilled the air beyond the pad's ability to warm the soil). 

 

my first crop of buds is small, and some of the buds that touched the plastic are burnt and useless.

 

i am irritated.  for one thing, i bowed the pvc from the ground on one side to the ground on the other side.  Next time I'll build tall sidewalls at least 6', so i don't bump my head, and have space to work all around the plants.

 

and of course, the small buds say that the heating pad is buried too deep.  at the soil surface the temp always read 48f or above, yet it may be that the roots suffered a loss of efficiency from being so chilly.  (and the roots didn't go more than 6 inches deep).

 

additionally, as tho i don't have enuf probs already, the sun's light may be too weak to raise normal size buds.

 

possible fixes:  supplementl hps.  

and dig up the heating pad and in its place, bury plastic water lines under the hoophouse and pump hot water through them. and maybe, to warm the air in the hhouse lay some warm water lines on the surface to warm up the ambient air from 60f ti 75f?

 

If you have the budget, consider buying liquid-cooled light fixtures - about $250 each.  Then get a 250-gal or so plastic tote.  Pump the water from the tote, through the light fixtures, then through the dirt underlying the roots.  That big tank of water will also store a lot of heat that can slowly dissipate into the greenhouse when the lights are off.

 

Best of luck.  This sounds like a major challenge.

[Wild Bill]

Try one of these

https://www.growerssupply.com/farm/supplies/cat1a;gs_greenhouse_heaters.html

 

Supplemental lighting would be a good idea too since winter days are shorter.

[trichcycler]

HID lights are awesome illumination in the winter darkness. One 600 watter hps lights up our whole yard! I tried the whole outdoor greenhouse, r32 walls, steel, solar clear roof panels, and 220 electric baseboard heat. Its a no go mostly. The light in the sky looked like a batman queue and heating to only 45 at night costed hundreds of dollars in December alone.  The cooling costs during the summer months was absurd either way using outdoor air or ac.  My par light meters were screaming mostly the whole winter days without the hps's. Steel on the roof now, ceiling in the room, insulated to r32/foil/bubble/foil like the walls.

Grow costs are exactly 1/3 the cost now compared to that year. Summer months cost the same as winter months now coincidentally.

 

I had a greenhouse grow before that one, 30x40, inflated roof, wood sides. I ran an outdoor furnace for winter heat, same frikken issues. too costly, no light, supplemental light was obvious to the sky. The summer temps were easier to control though in the greenhouse.  I buried a dumptruck of fresh hot cow poop

and ran  plastic lines through it and through the flood and drain beds too with water non stop. They did not freeze up luckily, but that didn't equate to "heat" either, except to the ice cubes around it.

 

good luck, I'm watching this one!

[t-pain]

17 inches , too deep!

[trichcycler]

If you have the budget, consider buying liquid-cooled light fixtures - about $250 each.  Then get a 250-gal or so plastic tote.  Pump the water from the tote, through the light fixtures, then through the dirt underlying the roots.  That big tank of water will also store a lot of heat that can slowly dissipate into the greenhouse when the lights are off.

 

Best of luck.  This sounds like a major challenge.

I used to dream of stuff like that. I really wanted my dehumidifier to be the reservoir for the drip system but didn't like the metal coils...... I did use the hid lights to power the solar (attic type) fans for circulation/ventilation.