Over-Mineralized Outdoor Bog

[jrod]

New poster to the forum, long-time lurker. Located in Delaware. I have a bog garden which i started in April. It has about 1in of horticultural charcoal as a base layer, then about 6in of 50/50 peat and play sand, then about 1/2in top dressing of long-fiber sphagnum (still not really growing yet). Plants are Sar. Scarlet Belle, a few VFTs, subulata and sandersonii, and some bog clubmoss. Everything broke dormancy with no problems, then all of a sudden all my VFTs melted, the the Sar. started to lose leaves as well. Tips of the clubmoss have also dried big time. I originally thought this was due to fungus gnats, which seem to come from all over to hang around this bog. Recently, though, I noticed a huge mineral spot under the drain hole from this container. Ever since, I've been flushing it as much as possible with distilled agua, but the plants don't seem to be doing much better yet. The leaves on the VFTs that are left are still turning black, and the Sar. still looks sad. The problem was most likely caused by using unwashed play sand.

After the lengthy description, I've got two questions....

One: Should I try to repot the plants and start the bog over next year, or keep flushing and hope for the best? I haven't noticed any more mineral deposits since I started the flushing.

Two: What's the best way to wash play sand or pool filter sand? I've got a huge tub of CP potting mix I'd made up, which I'm going to dump and remix. I'm going to use the larger-grained pool filter sand for this, but I'm not sure about washing it.

Any thoughts are very welcome. I've got a few other posts going throughout the forum, trying to answer some varied plant questions. Cheers.

 

[Tamlin Dawnstar]

Sounds like the sand is the problem to me too. Also, the charcoal was not a good idea. Charcoal absorbs the salts, that's true enough, but over time the material breaks doen and whatever salts were retained are released back into the medium again. This mistake caused to loss of my entire terrarium collection back in the 80's. The terrarium was productive for a decade, then pffffft. My feelings are that you need to start from fresh. I advise that you take up the plants, rinse off the media and repot into fresh mix. The pool filter sand is the way to go...playsand is very variable in composition: could be good or could be bad. Rinsing sand and peat are advisable, esp. for Drosera and Dionaea. Sarracenia seem less fussy about slight mineralization. I suggest you check the runoff water from your bog with a TDS meter. Maybe you could borrow on from your local municipal water supplier. Readings should be not above 150 PPM. Bog drainage is a good idea for long term success and should be provided by means of a removable plug to allow excess water to drain off. Best of luck with your project!