NEPENTHES GROWING TIPS
Nepenthes spp. grow in a wide range of environments and conditions, nearly as many as there are species. It is very difficult to summarize these growing conditions in a few words to suit all species and /or hybrids, although the hybrids are usually more vigorous and adaptable to a wide range of conditions. What follow are basic guidelines to give the hobbyist or the serious collector some helpful information based on our years of cultivation in and out of greenhouses. Improvements can be made to these to suit the specific needs of specific species. Your growing environment will also influence any further beneficial modifications. Most of these will be trial and error. The basic requirements for plant growth are Light, Moisture, Humidity, Temperature, Nutrients and a suitable growing medium; this is the case for all plants including carnivorous plants such as Nepenthes. It is the ratios of these together to suit the specific plant needs that give optimal growth, bearing in mind that the cultivation needs of plants are usually different from their requirements in their natural habitat.
The pitcher of the plant is just an adaptation of the leaf and as such will naturally die off as the plant grows, as do the leaves of any plant. As a guide, each pitcher usually lasts a couple of months. They can be trimmed from the end of each leaf when they have died off to keep the plant looking tidy but this is purely aesthetic and not necessary for the plants health. Each new leaf produced should develop a pitcher if the growing conditions are suitable.
In our experience this factor is one of the most important in producing optimal pitcher size and coloration. Providing there is enough relative humidity (RH) and moisture in the potting medium there can be enough light to give a tinge of red/burgundy to the leaves. Plants can be acclimatized to partial sun, morning sun being preferable, full sun all day however, will wash out the colour and stunt the plant. This they do quite quickly, with any damage usually limited to older pitchers burning or dehydrating but the plant remaining healthy. The next new pitcher has usually adapted and the plant will settle in. As a general rule, the brighter the light, the larger and more colourful the pitchers. Moisture must be maintained at all times, especially in drying winds and on hot days. As a guide, a bright position with high indirect light is acceptable. If plants are grown under shade cloth, a level from 50% up to about 80% produces good results. If under polyfilm, the white colours are preferred. On saying the above though, the length of the daylight hours also has a bearing on the amount of light your plant receives. In most areas the plants tolerate the loss of light hours but growth is a bit slower and watering may need reducing. Although Nepenthes do not have a dormancy period like a lot of other carnivorous plants, the lack of light does slow them down. A good indication that your plant is receiving the right amount of light is, as mentioned above, pitcher size and coloration. Another alternative if your plants are suffering from the reduced day length is to provide a couple of hours of artificial light, that is, if your situation enables you to do so.
It is important that moisture levels are maintained at all times when growing Nepenthes. Unlike a lot of the other carnivorous plant species, which like to be kept quite moist to wet during their growing season, Nepenthes like to be kept moist. Damp is probably the best term to describe their needs. Water quality is another issue in growing carnivorous plants (CP) where Nepenthes differ. Although all CP appreciate good quality water, that is low in dissolved salts and minerals, Nepenthes are quite forgiving in this case. It is not that they don’t appreciate good quality water or if available, rainwater, but we have witnessed them growing well with white mineral deposits on their leaves!
When cultivating Nepenthes it is most often advised to grow them in very high humidity, in the vicinity of 70-80% or higher. In our experience this high humidity can cause more harm than good in the greenhouse environment. Unfortunately a lot of disease and harmful bacteria also thrive in these greenhouse microclimates. We find that the humidity around the plants is usually maintained to an acceptable level by their moist potting medium with the plants growing well with the fluctuating humidity levels that normally occur during the day. These levels usually range from 50-70% during the day and up to saturation, 100%, at night. While plants growing in an outside environment will experience lower levels than this, as long as the potting media is kept moist there seems to be little detriment.
In our opinion, this is another factor that has had limits that are too strict set on it. While there are limits that specific plants will not tolerate, such as high temperatures in the case of the strict highland species/hybrids and very low temperatures with regards to the lowland varieties, again these plants are quite tolerant of temperature fluctuations. In the plants natural habitat the temperature fluctuates daily, even moment-by-moment. One has only to spend a few hours in a highland Nepenthes habitat to experience these quite dramatic temperature, humidity, light, and moisture fluctuations. One moment it could be bright and sunny, next it is cloudy with low light and 100% humidity and next it is pouring with rain, only to bathed in bright sunshine a couple of minutes later. The high ultra-violet radiation due to the high altitude and reflections from the water droplets on all the wet surfaces is the next factor to assault these plants. On the other end of the scale I have been told (pers. com.) and have seen photos of N. rafflesiana growing in pure sand which was that hot in the middle of the day it would have burnt the soles of your feet if you were to walk on it. So as can be expected Nepenthes are quite tolerant and hardy.
The many cultivars and/or hybrids we produce here in our nursery will tolerate temperatures from 5oC – 35oC(40oF-95oF) and many have experienced extremes down to 1.5oC(35oF) without any ill effect. Higher temperatures can also be tolerated with these cultivars and the lowland species provided a high humidity is maintained.
We would suggest, though, if you are looking at collecting the species and rare hybrids, some research into their specific needs would be beneficial. Except for a few species, an average temperature range of 15oC – 35oC (60oF-95oF) with some air movement, will grow most Nepenthes species successfully. The temperature change from day to night being beneficial.
Most growers have their preferred growing medium and one will work in one environment and one in another. The basic factor to keep in mind when selecting a potting medium is that it must be both open enough to allow good drainage but also be able to hold sufficient moisture for the plant in its environment. Some of the commercial bark blended potting mixes available for Cymbidium and Dendrobium orchids are suitable for Nepenthes as long as they do not contain fertilizer. We use both our commercial coir(coconut) based medium (coir chip and perlite) and pure Long Stranded Sphagnum moss with good success. If we had to recommend one, we would always choose the sphagnum moss. This gives us not only good success in growing the plants but it is also a good indicator of the plant’s environment. In a lot of cases the highland species of Nepenthes grow naturally in live sphagnum moss so when the moss starts growing in our cultivation houses this is a good sign that the conditions are correct. Both the lowland and highland species grow well in Sphagnum moss. The only problem I have heard with regards to growing in Sphagnum is the tendency for it to slime up and break down quickly in areas where the water contains some minerals.
The basic thing to remember with the nutrient requirements of Nepenthes is that they are carnivorous plants and best results are obtained giving them the insects or small animals they have evolved to digest for their needs. The plants are very efficient lures and traps. You can even see small indented specks, that are sometimes brown to black, on the leaves, stems and pitchers which are nectar secreting glands. These are part of their lure for the prey. We have seen plants solely supplied insects on a regular basis and their quality, size and hardiness is evidence enough.
We hope that the above tips help in the cultivation of these marvelous plants or at least have pointed you in the right direction. Above all though, if your plants don’t seem to be growing well don’t be frightened to experiment with the above factors as the plants usually respond quickly to the right conditions.
A GUIDE TO ESTABLISHING NEWLY RECEIVED PLANTS FROM US
This is a guide to establishing newly acquired plants from us after we have prepared, packed and shipped them from our nursery.
Prior to packing the plants are trimmed, inspected and have Sphagnum moss packed around their root ball and any excess moisture removed. Along with the packing and travelling, this can leave the root ball slightly compressed. Therefore the following should enable growers to establish their plants, maintain the pitchers on them and have them quickly start growing in their new environment. This is as long as the other criteria for growing healthy Nepenthes and/or Heliamphora are met. Namely, enough light, moisture, nutrients, correct temperature range and an open well drained growing media.
A quick reference guide:
Light- enough so you have good pitcher coloration but the leaves are not stunted and a washed out yellow in colour.
Moisture- enough so the plants are constantly moist but not wet or sitting in water (a couple of exceptions).
Nutrients- Live insects are always best but if your plants seem yellow or stunted and meet the above criteria, a weak fertiliser can be applied as needed.
Temperature Range- Find out the temperature range of the plants prior to purchase and aim to provide as close to this as possible.
Growing media- We recommend an open well drained media with lots of air in the mix. We use and recommend Coir (coconut) chip and large perlite or similar for lowlands and if your water quality(low dissolved minerals/salts) is good, pure Long Fibre Sphagnum for highland plants.
As a general rule it is best to avoid using peat moss as it is too acid and compacts too much.
What to do when you receive our plants:
After you unpack your plants and remove the plastic bag, remove the excess sphagnum packed around the roots by shaking gently or swirling them gently in a bucket of water.
If the plants were growing in coir, their roots will easily fan out. With these, spread the roots on top of your partially filled pot and top up with mix, stake if necessary and water in.
However, if the plants were growing in Sphagnum, their roots will usually be growing through this media and these will have to be swilled around a bit to loosen it up. Do not pull the sphagnum moss off the roots too much as you may break them. After you have done this, spread the roots out a much as you can in the new pot and pot up.
Once the plants are potted, a small amount of water that will give a level of 12-20 mm from the bottom of the pitchers, should be poured in. This will help the plants establish quicker while they acclimatise to their new environment.
Then keep the plants just damp and with high humidity for a few weeks and they should grow well.