Monday, April 21, 2014

Cultivation Guides: Preparing Media

This is part of a series of posts describing various aspects of cultivation, which will hopefully be useful to new growers trying to solve the challenges of growing carnivores, and experienced growers who are always looking to improve their collection. The full series can be read here, or by topic on the Series page.

Carnivorous plants have fairly specific needs when it comes to their media, and carnivorous plant-appropriate soil isn't available for purchase most places. This means that most growers mix their own media to suit the needs of individual species or genera or whatever subcategories lie between. The most common "CP mix" is a 1:1 blend of sphagnum peat and aggregate, usually coarse silica sand or perlite. Long-fiber sphagnum moss is used for some species, while others really want to live in live sphagnum. There are also other, more complex blends used for Nepenthes or Pinguicula or Cephalotus, but I don't have any of those in my collection at the moment (except for one P. gigantea) so I can't comment on that.

In addition to just mixing the materials properly, one must also wet the peat, and ideally clean the media somehow. Carnivores like nutrient-poor, low mineral content soil, which is particularly important when using tray watering, as I do, since nutrients and minerals don't get flushed out very readily when standing in water. It's also a good idea to wash out any spores that may lead to undesired moss or algae or fungus growth.

I learned how to rinse my media from Grow Sundews, where he strongly emphasizes the value of washing. However, the technique he elaborates is laborious, messy, tiresome, and wasteful – at least how I do it. I'm certain there must be a more efficient system than the one I've worked out myself. Rinsing the sand is actually not bad, but the soaking and wringing out of the peat takes a long time, and I end up throwing out a lot that gets mixed up in the water. A few days ago I decided to try simply running water through the pots to flush them, which is a technique another grower shared with me.

I began with a bucket of peat and sand.

Mixing peat and sand in a bucket.
Bucket of media. I have several buckets lying around the backyard that are used for this purpose.
I also wetted some long-fiber sphagnum. This is from Chile. The best stuff comes from New Zealand and is also the most expensive. The Wisconsin LFS I bought when first starting out is trash and I regret the purchase. It was full of grass and whatnot that I had to pick out as I rinsed. No fun.

Rinsing and hydrating long-fiber sphagnum moss.
Long-fiber Chilean sphagnum moss. LFS is very easy to hydrate and wash, and I would use it much more if it were less expensive.
I don't use much LFS, since it's relatively expensive, but I like to line the bottoms of my pots with it to keep the peat/sand mix from falling out and to provide a nice wick for the water. I pack it in about a half inch.

Layer of long-fiber sphagnum at the bottom of a pot.
Some plants like to live in all LFS, but for the rest I just do a layer at the bottom.
I then filled my pots and attempted to run water through them. However, my mix is somewhat heavy, and water definitely did not drain freely. I added a bit of perlite, which may have helped somewhat, but I think the real solution will be to spend an afternoon really fine-tuning my mix with a variety of different aggregates. I also suspect that the bale of peat moss I have is particularly fine – I would definitely prefer something a bit coarser to improve aeration and drainage.

Flushing the pots.
Flushing the pots. I used the bucket to catch waste water, but ended up not doing anything with it. Oh well.
As you can see there was much pooling of the media and floating of the perlite (I don't really enjoy working with perlite). I had to carefully pour some water, wait for it to slowly drip through, and then re-apply. It was better than constantly wringing out peat, but not by much.

I was lucky to have prepared the pots, as some NASC plants were delivered later that day, and 6 pots was perfect. I'll have pictures of them soon. And if I stumble upon any improvements to my media preparation, expect to hear about it here.

1 comment:

  1. I'm using 1 part coconut coir and 2 parts quartz sand (3-4 mm diameter), is good for my d. omissa and spatulata.