FlytrapCare Carnivorous Plant Forums

I have an 8'x2' grow out area indoors under LED lights. I use mostly 2" pots in trays of water. I add rain water water (rain water TDS is about 10 ppm) with Max Sea fertilizer (varies from 0-180 ppm TDS) to the trays. I have a moderate amount of algae growth in the trays. Enough to be really annoying. What options do I have to limit or eliminate this algae?

I believe I read that Maxsea causes quicker algae buildup.

Do you mean algae in the trays under the pots? or algae on the peat medium that the plants grow in?

And what kind of seedlings?

If it's just the trays, let the trays dry out between waterings. Algae can only grow in wet conditions. Your peat/moss mixture should be able to hold enough moisture for a few days.

Rinse out the trays and give them a good scrub from time to time. You may also consider increasing air movement in your grow area. A tiny fan can work wonders.

The algae is in the tray water. Seedlings are mostly sarracenia, some drosera, and a couple other random things. I do rinse and scrub the trays our occasionally, but honestly the algae comes back fast (within weeks). I would like others opinion about letting the trays dry out. Since I would like to fertilize through the tray water the fertilizer gets very concentrated when the tray water evaporated way down.

I'm thinking a better solution may be to try to fill the trays up more and cover the exposed water areas if possible.

I will try to post photos in the next few days.

Why are you putting fertilizer in the water? I'd think that would eventually kill your CP seedlings.

htbm wrote: ↑Sat Dec 14, 2024 3:06 am Why are you putting fertilizer in the water? I'd think that would eventually kill your CP seedlings.

This is one of the suggested methods to fertilize carnivorous plants in trays. It's dilute fertilizer at a closely monitored (by TDS meter) amount.

chrisaggie wrote: ↑Tue Dec 17, 2024 9:47 pm This is one of the suggested methods to fertilize carnivorous plants in trays. It's dilute fertilizer at a closely monitored (by TDS meter) amount.

Never heard of that, but I'm no expert. Still, we go through all the trouble of making sure our media are fertilizer free, rinsing etc. to make sure we really get as much of the minerals out as we can, and such... to then go and purposely put fertilizer back in? Anyway, whether that's helpful or harmful to the CPs, it sounds like it's feeding the algae.

So, I’ve been thinking about my algae issue. I’ve realized it’s not really a ‘problem’ as I thought, more of a minor nuisance. I’ve rearranged my trays so that the space between pots where the light hits the water is minimized. I think this is the best solution. I’m gonna have way too many Sarracenia seedlings next year.

htbm wrote: ↑Sat Dec 14, 2024 3:06 am Why are you putting fertilizer in the water? I'd think that would eventually kill your CP seedlings.

Sarracenia seedlings benefit from a little diluted fertilizer. Their roots can still take up some nutrients, and they grow much faster. You can read more about it in this article.

chrisaggie wrote: ↑Wed Dec 25, 2024 9:45 pm I've rearranged my trays so that the space between pots where the light hits the water is minimized. I think this is the best solution.

This will put a huge dent in your algae nuisance problem. All the fertilizer in the world won't do the algae any good if they don't get enough light to utilize it.

One other "angle" that you can use: instead of putting diluted fertilizer in the trays, just give your Sarracenia a drink of diluted fertilizer every 3-4 weeks. It'll soak into the soil where the roots can pick it up, greatly reducing the amount in the tray water.