Monday, March 25, 2013

A Watched Cactus Never Grows

     So I had neglected my cactus for about a week (terrible, I know); things had gotten busy and they skipped my mind. So I went to check up on them, expecting the worst, but was pleasantly surprised to see some health rapidly growing grafts. The pereskiopsis were growing rapidly as well, twisting and contorting as they continued to grow, even as they pushed up against the tops of their growing compartments. I noticed that the soil, almost across the board, was dry...To dry, under normal circumstances. The plants all seemed quite content and healthy though. I would have expected some minor wilting had I known what the condition of the soil had been, but the foliage all seemed very health and vibrant. Here are pictures of some grafts that I was especially happy with:

Astrophytum Myriostigma

Turbinicarpus Jauernigii

L-Trichocereus Bridgesii, R-" Pachanoi

     Just for the record, I DO NOT recommend letting your cacti dry out completely between waterings; the root structure of cacti is such that excessively long dry periods can cause root death, and can open the door for rot upon rewatering. If you are cultivating mainly peresiopsis like I am (or other jungle-type or epiphytic cacti), you are a bit better off, as these cacti, in my experience, tend to be more resilient to stresses such as these. Once again, this is why grafting with pereskiopsis can be such a boon to the cactus enthusiast and collector; as many of the pitfalls associated with the cultivation of collectible and/or ornamental cacti are related to soil, root rot, watering, etc., these are not of such major concern when pereskiopsis serves as your rootstock.

     It is amazing how the pereskiopsis just keep on growing and growing, as the pictures below clearly show. It is amazing as well, that they grow at this rate (grafts as well) with very modest growing conditions, in terms of light and soil.

Those are some twisted sisters! I almost feel bad for them :)

     I think it is about time I touch on fertilization. First off, I fertilize every time I water; this may sound excessive, but I use a rather dilute nutrient solution. My nutrient solution is mixed fresh every time I water, and consists of half strength Cactus Juice and quarter strength Miracle-Gro All Purpose. As you can see this isn't very strong at all, and I have noticed no adverse affects from these treatments, only healthy growth. As stated before, I now am a die-hard top-waterer. I used to ONLY bottom-water, but as the collection grew, it just became too time consuming to water all of the trays in this fashion. Also, I try to always spray the foliage gently with pure water (especially the grafts) to prevent (even if unlikely) any burning. That is about all for today. Stay tuned, as things warm up here in the frigid Northwest I hope to get some outdoor experiments going. Thanks for reading, and happy growing.

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Sunday, March 17, 2013

What is Cactaceae?

I thought it would be nice to give people an overview of just what a cactus is; what differentiates them from other plants, and what purposes their most distinct features serve. This may seem elementary to some, but I like to get back to basics from time to time, and I think most who read this will learn something from it. Here we go!

A cactus is a plant that is a member of the family Cactaceae. This family is of course within the kingdom Plantae, but further more, Cactaceae is of the order Caryophyllales, which encompasses many families of flowering plants, many of which posses some of the features of cacti; succulent-type leaves for one, which reduces surface area and thereby reduces moisture loss through evapotranspiration. Some members of this order don't bear much resemblance to cacti at all, and their inclusion is often based on genetics.

Back to Cactaceae, the typical features of cactus serve important purposes. The absence of leaves (except in one of my favorite cacti, Pereskiopsis, though this trait hasn't developed in many other species as well), is an evolutionary adaptation to combat moisture loss in the arid environments in which these species have developed. Some tend to associate arid or dry, with hot, but this isn't always the case; there are many species of cactus which are in habitat in the northern mid-west of the United States, up into the Dakotas and further north, where it can get incredibly cold (check out the lophophora blog for some pictures of some of these such cacti in cultivation). These northern areas, while they can experience extreme cold and copious amounts of snow, are relatively arid (or dry, or lack much available water), and the latter condition is more or less typical in most cactus species' native habitats.

Here you can see a rainfall chart of the United States. You can probably guess that the red denotes low rainfall, going on up to the blues and purples which denote heavy rainfall. Much of the northern mid-west has an annual rainfall in the 10-20 inch range; pretty dry where I come from.

The arid climate which is home to many cactus has spurred the adaptation of, not only loss of leaves, but the development of ribs. Since the cactus has shed the leaves, and reduced its overall surface area to combat moisture loss, some may ask why not get rid of the ribs to reduce surface area even more? The answer is, because the ribs typical of most cactus (though less pronounced in some species), increase the plants ability to take in water when it gets it. The ribs, as you have noticed when you neglect your cactus and forget to water, will shrivel somewhat, but after you water it you will notice the ribs becoming full and firm again in the days that follow; the ribs can swell to hold moisture to get it through until the next rain (or the next time you remember to water it). Species from especially dry areas have developed a spherical shape (these are many of the species we prize, and that are widespread in collections, such as Astrophytum, Ariocarpus, Lophophora, etc.), which is the best possible structure for retaining moisture and limiting its loss (the most volume with the least surface area).

Another adaptation with the purpose of limiting moisture loss, though not visible to the naked eye, is known as Crassulacean Acid Metabolism. This process is complex, and it could have several articles of its own, but I will try to simplify it. Most plants, during the day, are constantly taking in carbon dioxide to use to carry out photosynthesis, and excreting moisture and oxygen in the process; this process results in a very high moisture loss through the plants pores (known as stomata or stoma), as the pores are left open to allow carbon dioxide in, but at the same time moisture laden air inside the structure escapes. Cactus and many other species of plants have found a way around this, through the Crassulacean Acid Metabolism, also known as CAM. Essentially, with CAM, the plant's stomata only open at night, when it is much cooler (and the air is often more moist at this time), to take in and store Carbon dioxide (and any moisture vapor that comes with it). During the day, the stomata close, and the plant uses the carbon it stored during the night to carry out photosynthesis. This could be the single greatest (or at least one of the top two or three) adaptations that allow cactus to inhabit the harsh environments they do.

Another characteristic that many cacti posses, spines, serve a couple main purposes. The first, and main purpose in my opinion ,as you would guess if you have ever been stuck by one, is to keep away herbivores (and humans probably). The second main purpose is to provide some protection from wind and sun, both of which can cause moisture loss. While we're on this topic, we should discuss a key part of cactus anatomy, the areole. This feature is specific to cacti, and it is from this small organ that spines, glochids (really nasty spines), flowers, and new growing tips come out of. This feature is indicative of a cactus; if you see an areole, its a cactus basically.

The root structure of most cacti consists of mainly fine feeder roots, an adaptation to limited availability of water (see my article The Best Cactus Soil for a little information on cactus root structure). These roots are typically shallow to uptake water before it can drain down through the soil, and can spread out a considerable distance around the base of the cactus, for essentially the same reason. Some cacti, such as many of the aforementioned spherical, or globose, cacti, posses large taproots. These act in a couple capacities for the most part. For one, they act as a further means of water storage, and a good one, since they are not exposed to the harsh sun and drying wind that the aerial portion is. They also stabilize the plant and help keep it from being uprooted, and new growing tips can spring forth if the head is damaged or removed, provided there is a sufficient portion of the plant intact. Then there are species of cacti, often called Jungle cacti (or epiphytic cacti), which climb, or grow primarily in trees, and develop roots anywhere along their stems where there is an adequate growing medium (much like ivy, briars, etc.).

Well I think this is going to have to be part of a series. This was just something I wanted to touch on, hopefully I can add more to this in the future, but I think we covered some good territory. I like to get back to basics from time to time, and every once and a while I learn something new or relearn something I forgot, hopefully you guys did to. Thanks, and stay tuned.

Sunday, March 10, 2013

Top Heavy Grafts and a Little About My Setup

Here are some pictures showing what can happen when you graft on a pereskiopsis that is a little too much on the tall side. You can see just how much they lean; if they didn't have the sides of the tubs they are planted in to lean on, they probably would have up-rooted themselves. The amazing part is, they continue to grow like always. Pereskiopsis is a very adaptable plant, and can put up with just about anything. The scions in these pictures are all Trichocereus Peruvianus, except the one that has been topped; I think this is a Macrogonus. They all have tags at their base, but with the way they are leaning it's hard to tell where they all start.
The trays they are planted in hold about 30 pereskiopsis each, and are about 13 inches long by 8 inches wide, and have only about 2 inches of soil (see The Best Cactus Soil). Pretty amazing huh? In addition to this, 4 of these trays (roughly 120 pereskiopsis and grafted pereskiopsis) are placed under just 26 watts of fluorescent light, and they all grow like weeds.
Everyone can have a cactus collection, and they can do it on the cheap. I will get into the details of my whole set up in the future. Thanks, comment and subscribe to my feed.


Monday, March 4, 2013

Pereskiopsis Seedling Grafting 101

This will be a short tutorial on seedling grafting onto pereskiopsis. This will cover the method I use myself, and I have found this to work at least as well as any of the techniques out there. The main reason I do my seedling grafts this way is for ease and simplicity. Other methods I have seen employed include letting one end of a slightly weighted piece of glass rest on top of the scion for a number of hours (if the description doesn't make sense, trust me, trying to get it to work in real life will really give you a headache), or leaving a pen cap or something similar over the scion for a certain length of time... These methods have proven to be a real pain in my experimentation.

The fact of the matter is, you are going to loose some grafts no matter what you do, so you might as well not spend all day doing it. My method is quick and easy, and is more or less as effective as any other method I have tried. So lets get right to it.

The supplies you are going to need are as follows:

1. A razor blade

2. Some rubbing alcohol
3. A clean rag
4. Some squares of plastic wrap (about 2 inches or so)
5. Some thin wires (ones pictured are 22 gauge) bent like so
6. Some healthy young pereskiopsis plants
7. Some healthy young cactus seedlings
Now, first things first, lets get an overview of the process and some preliminary tips. First off, we are going to attempt to join the seedling and the pereskiopsis (duhhh). We are going to facilitate that union with the plastic wrap and the wire. the plastic wrap will go over the scion once it is in place and the wire will hold the plastic wrap in place. These two pieces can be reused over and over again (usually). I made the little wires out of 22 gauge wire rope; separated the strands, cut them into little pieces, and bent them to shape. In case you were wondering why the wire is shaped the way it is, it is because when it comes time to remove the plastic, it is much easier to remove the wire by grabbing each end between two fingers and pulling them apart, rather than having to pick at the two wire ends to try to get something to grab on to (all that fiddling can knock scions off, trust me). You can probably figure out how the squares of plastic wrap were prepared, and what their use is, so I won't bore you with that.
The condition of the plants and soil is the next topic. Make sure your seedlings and pereskiopsis are healthy and show no signs of disease, rot, etc. Also, make sure your soil is of the proper moisture level; not sopping wet, not bone dry, but pretty much right in the middle, or leaning a little more to the wet side is fine...Just don't graft on a dehydrated pereskiopsis.
Now that we have covered that, I think we are ready to get to the actual grafting.

First and foremost, you are going to want to clean your razor blade using the rag and rubbing alcohol. Set the cleaned razor blade somewhere where it wont get dirty (on top of the clean rag is a good place).
Now you have to select the pereskiopsis most suitable to be grafted; I like to pick the thickest stocks I can, this gives a nice little platform for the scion, but make sure they are not too stiff and fibrous, as this can inhibit the union. Here is the one I chose for this demonstration:

Once you have found a nice pereskiopsis, take the top off (just cut off enough so that you will have a large enough base for the scion) and then remove all of the leaves perhaps an inch or so down from the top. Also, if you notice any areoles closer that maybe 1/8 of an inch from the cut, gently cut these out; when your graft is young, these may start producing shoots, and the swelling associated with this, in such a close proximity to the scion, could disturb it or even push it off completely. Here is a picture of the pereskiopsis above after this treatment:
Once you have done this begin looking for the best seedling to graft onto your pereskiopsis. I like to pick out the fattest and healthiest looking ones first, but it is up to you; just don't pick any that are discolored and/or deformed (its a good idea to get rid of these altogether). Here is a particularly nice looking Hylocereus Undatus that I chose to graft to this pereskiopsis (there are no roots on this seedling because when I tried to pluck him out he started to pull all of his buddies out with him, so I had to cut him off at ground level):
Once you have picked your seedling, gently grab it and pull it out of the soil. Shaking off the excess soil is a good idea even though you are going to be cutting off the bottom half anyway, as it just helps keep your razor and the scion cleaner. The next step now is to cut the scion so it can be placed on the pereskiopsis. I personally like to cut the seedling at its widest point (roughly the middle of the above-ground portion in many species), or at least so that there is sufficient width at the cut so that it isn't wobbling around to much on top of the rootstock.

Once the seedling is cut, quickly, and while the seedling is still in your fingers, slice a very thin piece off of the top of the pereskiopsis, to ensure that both surfaces are fresh when joined. Then place the scion on top of the pereskiopsis and press down gently to make sure there is no air between them, then grab your wire and plastic wrap. First, here is a picture of the above seedling after being cut, and initially placed on top of the pereskiopsis:
Gently place the plastic wrap down over the scion, and while maintaining slight pressure on the scion, twist the excess plastic wrap around the stalk of the pereskiopsis and hold with your fingers. Then grab your wire, and push onto the stalk and pinch down around it until the plastic wrap is secure. Now is the best time to properly position the scion, by gently sliding it around and pulling on the bottom of the plastic wrap to keep it in the right position. Here is a picture of the scion once secured and wrapped:
This is a big topic actually, proper scion placement, so I will devote some time to it..Like I said before, you are probably going to lose a fair number of grafts no matter what you do, so don't go pulling your hair out trying to get the perfect placement. A good rule of thumb, in my experience, is to try to get the scion just slightly off center, and make sure the cut surfaces of the scion and the rootstock are in full contact. If you do both of these things you will be a lot better off than you would be if you sat there all day with your micrometer trying to get a perfect placement; in fact, messing around with a graft too much can damage it and have the opposite effect. Its a crap-shoot to a degree; I have had grafts that I was sure were going to make it bite the dust, and grafts that I was sure were going to fail do awesome. All in all if you follow these recommendations though, im sure you will have respectable results.
I usually leave the plastic on for three or four days, and then take it off and treat the graft as I would any other plant. I know a lot of people recommend a humidity chamber for the first week or two, but honestly I haven't had the chance to try that myself and I still get satisfactory results. Perhaps in the future I will be able to experiment with humidity chambers, but I think I will be doing things this way for the near future at least.
This was a brief tutorial on grafting with pereskiopsis that I have been meaning to do for a long time, but couldn't find the time, so I just threw this one together. I hope to be able to give you guys some pictures of new grafts as they start growing soon. Thanks for reading, comment and subscribe.