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Hi all... I am in the process of building a "mini-greenhouse" due to an expanding collection, and have a few questions if I may... The unit will be attached to the back of my house, will be about 10 inches deep, 40 inches wide, and 5 feet tall. Slanted plexiglass top, plexiglass door, sides, and shelves. It will sit about 3 inches away from the wall, with the back made from screen for air circulation. And bug proof! Due to limited space and positioning, the cacti will only get about 5 hours of direct sun in this, but what should the shading be? 30% seems to be the average I've found. I have a light meter to check. I am thinking of either shade cloth, tinting, or screen for shade. Any input would be really appreciated!! Thanks as always... Joseph

30% shade cloth? The standard convention is that it would block 30% of the light. This is considered only a low level of shading and you probably won't find anything lower. Should be fine, although there are certainly cacti will will grow well under heavier shading. 70% shadecloth (30% of the light hitting the plants) is pretty high, too high for desert cacti.

If the sun is only in the morning then you might not need shading at all. A wall already lowers the light level more than you'd think, although it might reflect a fair amount of extra heat onto the plants.

I would guess it depends on where you live - Florida sun would be stronger than England or the northeast. I have a 13 by 8 lean-to in NJ & by tucking the epis up against the roof overhang & using stacked shelves I've not needed shade cloth. Watch your plants carefully, acclimate them gradually & they should tell you what they need.

I would advise against any kind of window tinting film as most film blocks out from 90 to 99% of the suns UV rays.

Hi Joseph

I use window screen. Using a light meter, as accurately as I can, I think I am getting about 30% shading (70% transmission). My plants in California get burning hot sun all day long. The shade cloth seems sufficient for my diverse collection (nothing über-rare).