Cultivation
terrestrial species

My standard growing technique is simple. I use a mixture of peat and sand in a three inch pot. I have them in trays, and I let the water level fluctuate between just under the soil surface and letting the tray become completely dry. I grow them under 4 standard fluorescent bulbs, about 15 inches from the lights. My terrarium is simply a plywood box with a glass top and sliding glass doors. I leave the doors open a bit to allow for air circulation. The humidity in the terrarium is not especially high, around 50%, and the temperature varies between 19 and 30°C. I try to vary the photoperiod from about 12 hours in the winter to 16 in the summer.

Some species require modifications to this method. Some plants require a more open, dry medium, some require a higher water level, and some (at least in my care) require occasional repotting to keep them alive.

U. biloba, resupinata, juncea, leptoplectra and cornuta all grow with the water about 1-3 cm above the soil surface, but I still use the standard medium. Other plants, such as U. praelonga, U, prehensilis, U. flaccida, U. uliginosa, U dichotoma and probably others benefit from a few months of the year growing in this manner. Some of these species will respond to the different conditions by changing the size and shape of their leaves.

I have until recently been growing U. humboldtii and U. nelumbifolia in pure long fibre sphagnum with the water level kept at the surface of the medium. However, I recently noticed that my plants had almost entirely rotted away, and the media smell exceptionally bad. Now I have them in a mixture of live sphagnum and rock wool, with a normal utric watering regime.

U. hispida is a very slow growing species, and seems to grow on a seasonal cycle, with new growth coming in the spring. On advice from a fellow CPer, I grow it in a slightly larger pot, since the leaf rosettes are located far apart on the stolons. I was also told that the soil level should slope across the width of the pot, so that one side is under the water level and the other side above. However, as time has passed the soil level as evened out with no apparent negative consequences. It has even flowered from me.

Plants that require a lighter substrate include U. alpina, U. alpina x endresii, and U. quelchii, U. praetermissa. All of these plants grow in a mixture of long-fibre sphagnum and fine orchid bark (1:1), with a 1 cm layer of long-fibre sphagnum on the surface. These plants are not grown in standing water, but are watered much like regular houseplants. I soak them, and then wait for the surface to begin to dry out. I used to grow U. reniformis and U. geminiloba with this same technique, but have since moved them to a standard utric watering regime with better results.

There are two tricky plants in my collection, U striatula and U. aureomaculata, that seem to begin to die off occasionally, and for no apparent reason (since I wrote this, I have had absolutely no trouble with U. aureomaculata, but I still keep an eye on it). I have found that when this happens I have to start a new culture with a section or several pieces of stolon from the original plant. I was having some success at increasing the size of my U. striatula by removing most of the scapes before they could develop. This experiment was cut short by a disastrous pesticide experiment (see below).

I have attempted to grow U. menziesii in the past, without success. I planted my dormant tuber in live sphagnum and it grew happily for a few months. When it seemed to be wanting to go into dormancy, I let it dry out. It did not, however form a new tuber and was thus lost. If I were to try growing it again, I would try it on a windowsill, where it would get a more realistic temperature cycle and photoperiod.  

I have problems with slimy growth on the soil surface of some of my plants. From what I've heard this is not an uncommon problem. I assume that it is algae of some sort, although I have heard it suggested that it is a cellular slime mold (acrasiomycota). Of course, a few minutes with a microscope could clear things up, but no one seems to have taken this step.

I have experimented with a variety of media, and none seem to be any more or less prone to the slime. Some pots get it and some don't, but I can't attribute its appearance to any one variable.

The only technique I've found that works, is regular spraying with water. It seems to prevent algae formation by constantly disturbing the soil surface, although I suppose that it also serves to leach nutrients out of the surface layer of the soil. I have found that this technique works even better if there is a layer of sand on the top of the soil surface, but some species seem to have trouble growing with the layer of sand. Preliminary results seem to indicate that after a while things stabilize and the spraying can be done with less frequency, or even not at all.

Something else that may help is keeping the media a little bit drier for the first few weeks, allowing the pots to dry till the media begins to pull away from the edge of the pot, then giving them a few cm of water from the bottom.

The only other biological problems I've had are aphids, thrips, fungus gnats, and mold. Mold is mainly a problem with unhealthy plants. This can be solved quite effectively by changing the growing conditions. My first suggestion would be to repot a section of your plant in new media, rinsing off as much of the old media as possible. Mold is often attributed to low light levels, but in my experience it has usually been the result of poor air circulation.

Aphids can infect Utricularia and can damage flower scapes and slow overall plant growth. They can be difficult to spot on the vegetative portion of the plant, but will tend to climb the scapes where they are more easily seen. I have tried controlling them by picking them off by hand, but was unsuccessful. I eventually gave in and used a small amount of judiciously applied Diazinon (liquid form) and it solved the problem. When the aphids returned the following year, seemingly bent on revenge, I tried the same treatment. I think I was a little trigger happy with the sprayer because I severely burned many plants, killed two of them and nearly lost a third.

I have also had a severe thrips infestation, which along with a plague of aphids nearly killed a few of my plants. It was really amazing how fast the thrips could devour the plants. I only ever saw a few of the ugly little things (I'm sure their mothers' thought they were beautiful) but the damage was unmistakable: silvery-white leaves with tiny spots of dark green excrement.

Fungus gnats have been a part of my collection since I began keeping carnivorous plants. The flies themselves are look like fruit flies and are completely harmless. The larvae, which look like transparent worms with black heads, can be a problem for small utricularia species. Under most circumstances they are not a problem, but a heavy infestation can make it more difficult to establish new plants. Apparently there is a strain of BT that will kill the larvae, but I have never has a chance to try it. I just use "sticky strips" - bright yellow strips of flypaper that attaches to a small plastic stake. They can help to control the fungus gnat population, as well as allowing you to monitor the population.

There is hope, however. I managed to get some Orthene SP75 soluble powder insecticide. Apart from the smell (rotting flesh) and toxicity (which I try to think about), it was the answer to all my problems. Two applications, about a week apart and I haven't seen aphids nor thips since. It had no effect on the fungus gnats. The Orthene was difficult to find, but I eventually purchased it online from an agriculture/horticulture supply store. Please, if you are going to use this stuff, acquaint yourself with the risks and safety procedures, I cannot be held responsible if you inhale some and grow a third ear.  

If you are looking for the solution to your seed germination problems then stop reading now. I have little advice to offer on this subject. I have had seed germinate a few times, and almost always it was collected from plants in habitat, and very fresh. I have tried planting seed that my own plants have produced, without success. Most species don't seem to produce seed in cultivation anyway.

Recently I have a had a some luck with a few species of annuals (U. multifida, U. violacea and U. tenella) by spraying the pots with water daily. I'm not exactly sure about the function of the water spraying - I have heard that it serves to leach out growth inhibitors from the dormant seeds - but the most significant function is to control the growth of algae moss, liverworts etc. that compete for surface space. It is also important to continue the spraying regime until the plants are established, otherwise the competitors will take over again.

On the whole, however, the best advice I can give is don't bother. I have come to the conclusion that it costs me more per established plant to buy expensive living plants than to buy seed. It's tempting to look through the Allen Lowrie catalog and dream of the exotic and unusual species that you could grow, and the respect and admiration they would earn you from your peers. This has never worked for me. What has worked is spending money for some expensive plants, and then trading these plants for more plants. Of course, if someone has a fail safe method for germinating utricularia seed, please let me know.