Seedlings disappearing. White mold instead.

[abhikjha]

A weekly deep soaking is the wrong approach with cactus seedlings - the substrate should be kept evenly damp, never saturated. Commercial nurseries achieve this with capillary matting - the pots sit on a mat of wet, spongy material, pulling water up by capillary action They will never draw up more than just enough to moisten the media.

You can achieve the same thing by bottom watering with or without an absorbent mat under the pots. As long as the media isn't underwater it won't get saturated, so a thin film of water in the tray under the pots works well enough, though you have to water daily - I use a sprayer bottle for this.

Once the seedlings reach the point where they've completely filled the pot with roots, then you can transition to top watering.

That's very informative Spence. One question though - do you mean to say that a thin film of water under the pots for bottom watering and misting from top, we need to do both? If only bottom watering, then what's the use of sprayer bottle? Also, I don't have access to capillary mat in India, can I use few layers of cotton fibrous towels instead or cocopeat mat? I read somewhere that the spongy fabric we use in kitchen for cleaning slabs be also used for capillary mat.

[greenknight]

I mean just water from below - the only reason for using the mist sprayer is asw a convenient way to apply a small, metered amount of water and make sure it's spread out.

Lots of things can be used as improvised capillary mat. Some just use a thick layer of newspaper, which they replace each season, the old stuff going in the compost. Cocopeat is rot resistant, so it would be more permanent - it might work well, same with the towels.

Some commercial matting consists of a core of felt between layers of perforated plastic. I imagine the plastic just is to improve durability and make it easier to clean up.

[abhikjha]

Thanks Spence! It really helps.