Bright indirect light vs direct sunlight vs shade cloth

[abhikjha]

Hi all,

Since I couldn't find any credible info in past or on internet, I am turning to the expert community here for advice and suggestions.

I am a new enthusiast and over past few months purchased a lot of plants. I am in a tropical place(Mumbai) and in an apartment. In winters, due to the positioning of sun, I get ample sunlight through my South facing window. But now in summer, direct sunlight has considerably reduced. However, the room is adequately heated and we get very bright indirect light on the south facing window. Outdoor, sunlight is very harsh especially in late afternoon.

I have three options to consider to place my plants in summer:
1. On windowsill with very bright indirect light. I will adjust the watering schedule accordingly. There will be full air circulation (fan running with windows open)
2. Outside with no shade cloth. Sunburn could be a major risk I guess in this situation as sometimes wind stops completely.
3. Outside with 50% shade cloth. Just ordered it online. My question is with this 50% shade, won't the setup will be similar to 1 above minus air circulation?

I am tempting to opt for 1 above but my worry is whether they will grow appropriately without etiolation?

Cactus I grow are mainly Astrophytum, Melocactus, Discocactus, Gymnocalycium, few Echinopsis, few Mammilaria, few notocactus. I guess if I can get lighting right for my Astros, Gymnos, Melos and Discos, 90% of my plants will be covered.

Kindly advice on this as I am in a big dilemma!

Cheers
Abhik

[7george]

I keep most of my plants on windowsills permanently to avoid risk of sunburn and stressing them by change of conditions. Any cactus can be burned by sudden change of light and low (or hot air) circulation. Sometimes it happens even through double glass window. At other hand 50% shade is a significant, so maybe this will be adequate protection. If you are afraid of possible etiolation, after plants adapt for several weeks shade cloth can be removed or replaced with brighter one. Act depending of clarity of the air in your place and where the plants are held now. You can also split them into 2 - 3 groups according your expectations.

[abhikjha]

Thanks so much George for the response. It's quite a relief to hear that expert like you are growing your most of the plants on windowsill which I have been doing so far as well. Just because of the sun's position in summer, since sunlight is not falling on the bodies of plants through windows, I was thinking to take them outdoor. As far as heat or bright indirect light is concerned, there is no dearth. Air-circulation in room at window is also adequate as fan is always almost on with windows open. Listening to you and by researching on net, I am thinking to do following:

1. Keep Melocactus, Discocactus, Echinopsis, Gymnocalcyium, Astrophytum Asterias, Haworthias, Mammilaria, Sansevieria on windowsill in bright indirect light.

2. Keep Parodia, Astrophytum Myriostigma, Euphorbia, Coryphantha, Opuntia outdoor with some shade.

Do you think this is a fair approach?

Cheers!
AJ

[7george]

Sounds great, show us later how those plants adapted and bloomed.