How to Grow Your Seedling Cactus


Hi again. Thanks for all of your work on the web, you tube and the blog. I appreciate it.

I am moving to Utah and need to decide whether to take my tiny little seedlings with me. You might remember but I bought the small green tray and used coir and crushed carbon as one of your employees suggested. I also took your previous advice and bought your linseed oil and have given the tiny little green rice-sized cacti a few mists with it (1:1 with distilled water). However, I do have some questions:

1. First (a few questions), I hadn’t sprayed the seedlings in many weeks. A couple of days ago I noticed that two seedlings (is this the correct name?) were covered in a white mold of some type. I misted them again with linseed oil and today they look good. My question is – do I need to worry about this? How often should I mist with linseed oil, and can I overmist? I still haven’t put any holes in the container for fresh air – is the mold related to humidity possibly? They’ve been in the container, in a bubble window for 2 months. No direct sun, no watering, etc.

2. Second, as I mentioned before these are very special cacti to me and in some way I want them to grow to maturity for their own sake (sounds goofy I know, but..) – so I am contemplating giving them to a trusted friend to take care of. I’m concerned that such delicate seedlings couldn’t make it through a Utah winter (indoors obviously). I would be willing to use a reptile warming mat or anything if you thought that they would do as well in Utah as they would here. What would you do in this situation? Like I said, I am willing to invest some money to make cacti work in Utah, even if it means buying a serious light source for the winter months.

Thanks so much,

That was a long question. Let’s post the answer after the break…


It is time to give them some air, add some holes or lift the lid once a day and “blow on them” (adds some carbon-dioxide…) before putting the lid back on. I try and not over-use pesticides and I think if you give them some air they will stop having fungal problems. As far as growing them on under lights it really isn’t that hard and you do not need a “serious light”, just get a florescent light fixture with full spectrum bulb(s), (CR value above 85). Place it about six inches above the top of the dome. It will keep them warm enough and light enough to grow inside for their first year or so (depending on species).

We start all of our seeds under fluorescent lights that run 18 hours a day.

Good luck and have fun in Utah,


Now that’s a recipe for success.

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