Monday 30 December 2019

Guest Post: Carnivorous Plant Growing Guide

At some stage I will probably write some posts about how I grow carnivorous plants.

Unlike most of this blog, the following is not my work.  The following is a guest post written by Beauze Menzies.
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Media & Materials:
 
Carnivorous plants as a general rule need low nutrient soils based on sphagnum moss products such as peat or long fibered sphagnum which is often used for orchids. Using distilled or RO water is important unless your tap water is under 100 ppm (this number varies by species i.e. nepenthes can tolerate higher ppm).
 
For plants like pinguicula (pings or butterworts) using a soil mix low in peat that is well draining is important and mixes containing no peat have been used successfully. For pings, it might be of interest to try mixing your own soils based on cactus soil recipes that don’t require any real soil (so a rock based soil).
 
Bog CPs like Sarracenia can grow in a wide variety of soil mixes from pure silica sand to pure peat. However, a combination between the two ingredients is often used and is a safer bet than using peat or sand straight. This is also true of flytraps, but currently using long fiber sphagnum is a popular choice for growing them well. However, long fiber sphagnum is very light and dries out quickly, and when wet again, it can become a soggy mess.
 
Proper aeration seems to be key for all CPs.  To maintain aeration, peat is often mixed with course silica sand (free of contaminates) and/or perlite. Perlite has an annoying tendency to float to the top when watered and doesn’t look good. Another way to make sure nothing literally gets “bogged” down is to let the water tray dry out for a day or two between watering. This will allow air to get back on the soil and keep the bacteria down and can be beneficial for some CPs.
 
I use standard black plastic nursey pots placed in 1020 heavy duty nursery trays for most CPs. Flytraps have long roots so they benefit from taller pots. Many people use Styrofoam cups for this reason for their flytraps but it doesn’t look good obviously. For Drosera capensis I plant them directly in a 1020 nursery tray or similar tray and water them directly or place them in an even larger tray for watering. Getting white pots or somehow painting the pots white would be highly recommended if the plants will be outdoors.
 
Flytraps:
 
Venus Flytraps need full sun outside, tall pots, and whatever humidity you got naturally. Don’t stick them in a humidity dome! In hot areas they can be kept full time in a tray of water but a taller pot should be used so the soil at the top doesn’t become waterlogged.
 
Flytraps can be propagated clonally by divisions, leaf pullings, and nonclonally by seeds (Seeds do not need stratification but must be surface sown so not buried). 

A leaf is simply pulled off and floated in water under a light for a few weeks until a bud forms at the base. However, if the leaf does not contain a small section of the crown it will not take so you cannot just cut a leaf off. You can cut a young flower stalk off though and treat it like a leaf pulling and it will also form plantlets.
 
Sarracenia:
 
Adult Sarracenia should be grown full time outside. During the growing season they are kept in a tray of water, but some sarracenia such as leucophylla do not like having constantly wet feet so it is important to let the soil dry slightly between waterings which will help prevent rot too. During dormancy they are often brought into a protected area like a basement to protect them from sudden freezes. It is important to watch for rot in the crown and for mealybugs that live in the roots.
 
For large Sarracenia displays, many people build water tables which allow viewing from eye level and hold water. However, since the water can get stagnant this can also promote rot since it’s essentially a giant tray… and the rot can spread very fast with so many plants sharing the same water. Having the water table slope slightly and having the water constantly being pumped up and filtered will prevent this stagnation. This constantly flowing water could possibly also reduce the need for drying out times between waterings but this needs experimenting.
 
Sarracenia seeds need four weeks of moist stratification before surface sowing. Young Sarracenia grown from seed can be grown indoors and can skip their first year of dormancy. These young plants will need a grow light such as a T5 fluorescent or Marshydro 300 LED (see Darlingtonia). While these lights can be costly but using them correctly (16 hour days) can drastically improve juvenile Sarracenia growth rates. Another way to improve their growth rate is by using Osmocote pellets about an inch under the peat mix (https://www.carnivorousplants.org/grow/feed/sarraceniasoil) . In addition, many people foliar spray or fill the pitchers with ¼ strength Maxsea. One thing to remember with Sarracenia seedlings is that they will need repotting and more space as they get bigger. So, if you are not planning on culling heavily, be prepared for sarracenia overload.
 
Drosera:
 
Drosera can be grown outdoors or indoors depending on the species. If indoors they will need a grow light such as the ones recommended for Sarracenia seedlings but keep in mind that a purple LED will make viewing your Drosera difficult. South American Drosera are often picky about growing conditions and need high humidity. African species vary from capensis, which is considered the easiest CP to grow, to D. regia which needs porous soil and literally needs fertilizing. North American and European species tend to need long dormancies since they’re from cold climates (filformis and tracyi not so much?) but there is easier to grow forms such as the Hawaii form of D. anglica and the rotundifolia cultivar: “Charles Darwin” (If you can find this cultivar!).  Australian species…. No idea really except for binata which is easy to grow – the other Australian species look awesome though.
 
The larger forms of Drosera binate (marston dragon, multifida, etc.) do not flower often. To force flower them you can take them out of their water tray and only top water them occasionally. This will make them dry out a lot and they won’t be too happy. Just give them enough water so they don’t die. This took about a month for me. They should produce flower stalks at which point you can water normally again. If you want seeds, you’ll need to lightly rub flowers from different clones together to cross pollinate them. Interestingly, doing this did not get my smaller T-forms to flower so I am uncertain whether they are unaffected by this procedure or if they are were too small. If it matters, which I don’t think it does since I rarely chance the light’s timer settings, the binata started flowering in Autu
 
Drosera can be propagated easily by leaf cuttings which, unlike the flytraps, can be simply cut at the base and thrown in some water (https://www.carnivorousplants.org/grow/propagation/DroseraLeafCuttings).
 
Most Drosera species do not need special care if being grown from seed unless it’s a North American Species which will need stratification. Tuberous sundews need to be set outside to germinate since they will only sprout if the day length is right so it can take some time. Germination for common species like capensis will take two weeks normally but can take longer. Drosera also need to be surface sown like most other CPs since the seeds are so small. This also makes it important to make sure the seeds won’t dry out so covering the pot with a plastic bag is common practice until the seedlings have a few leaves (on all CPs actually). To make sure you have good soil to seed contact you could use a thin layer of pure peat on top of whatever peat mix your using and then put the seeds on top of that. This is a good idea if your normal peat mix contains lumpy bits of perlite.
 
Baby Drosera will need feeding. The best way is to rehydrate bloodworms by dipping them in water (the dew will not rehydrate them) and placing a tiny piece on one leaf of each baby drosera. This will take forever, and you’ll need tweezers and possibly a magnifying glass. I was able to get very fast growth rates on baby capensis that were planted in long fibered sphagnum by top watering them often with Drosera pretransplant tissue culture media (from phytotech) without sugar or agar. The seedlings did not suffer negatively from the fertilizing at all which makes sense because drosera in sterile tissue culture grow just fine on that media.
 
The Darlingtonia in both pots are the same age and from the same seeds. The only difference is the larger one is potted with S. leucophylla and has osmocote. Photo taken December 19th – smaller Darlingtonia went dormant Oct 17th.
Darlingtonia:
 
Darlingtonia need good light, a light soil such as live sphagnum, and a steady supply of water in their tray. Having the water be recirculated by a pump probably wouldn’t be a bad idea. However, the biggest problem with Darlingtonia is the fact they die in any sort of heat especially if the roots of an adult plant get hot (young plants are slightly more tolerant of heat). There is an easy solution to this though and that is growing them indoors with AC under a good grow light such as those recommended for Sarracenia seedlings. The annoying purple color of the Marshydro LED is something to consider when deciding which light to buy. The T5 is widely used, produces some heat, but I have no personal experience with it. COB LEDS come in daylight colors and could be an excellent compromise.
 
The darlingtonia will need a winter dormancy so make sure to decrease the light’s daylength at the same rate as the daylength outside as winter approaches so the plant can prepare for dormancy.
 
Propagating darlingtonia can be easy since they produce rhizomes which can be cut and used to grow new plants. More difficult if by using leaf pullings. Germinating seed is easy and while I used a six week stratification, it may not be required for fresh seed. Darlingtonia naturally produce seeds earlier in the year like flytraps which would suggest they too don’t need stratification and can sprout right away. http://sarracenia.proboards.com/thread/2382/darlingtonia-house-2015
 
Shortly after the darlingtonia seeds sprouted I had transplanted one of the darlingtonia seedlings to a pot that contained S. leucophylla seedlings and possibly some Osmocote. I have not given this individual dormancy yet unlike the other darlingtonia seedlings which are now in the fridge (not cold enough outside where I live). Before I put the other seedlings away though I decided to check if they were the same size as the seedling with the leucophylla. Surprisingly, the one darlingtonia with the leucophylla was double the size. I am not sure if this was because of the Osmocote or if the Sarracenia seedlings were beneficial in some way. If I had realized that transplanting the one to the leucophylla pot would speed up the growth rate so much I would have paid much closer attention to the details, but I had thought nothing would come of it.
 

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