Propagating Cacti from Seeds
Propagating Cacti from Seeds
Written by Friday, 23 December 2011 00:00
As you may know I am interested in cacti (or better yet in succulents plants) almost as much as I am interested in fish keeping. It is worth adding here that these plants are excellent “pets” when you are bringing up children, as is the case with me. This is because they do not require a lot of your time: they have a dormancy period stretching from mid-October to the end of March or sometimes to the middle of April. During that long stretch of time all you have to do is to keep them away from the rain in a quiet place (I bet they do not like noise while sleeping!) and let them rest … You will be rewarded when spring arrives by blossoming flowers of incredibly vivid colours and beauty. During the rest of the time (April to October), all they ask for is water once a week or so, and repotting every two to three years. Nothing more nothing less!
Propagating the plants is slightly more complicated, particularly if you decide to start from seeds: while some plants can easily multiply by cuttings (to name but a few plants of the genera Opuntia, Mammillaria, Agave etc propagate this way) many others cannot. As it happens some of the succulents I like the best belong to the second group (plants belonging to the genera Astrophytum, Ferocactus, Gimnocalycium).
In some cases the only way to ensure that these plants do not get out of the reach of hobbyists is to propagate them by seed. This holds true for all the plants listed in C.I.T.E.S, which are a lot. Legislation either explicitly forbids or regulates strictly the collection of protected plants from their wild habitat.
Having said that it is now time to describe how I managed to propagate my plants. Be warned, propagating this plants is extremely addictive, possibly even more than getting fish to spawn in your tanks.
The first thing you need is to get hold of some good quality seeds, ideally from “pure strain” plants. You can do this either by getting the seeds themselves or by acquiring some plants. Controlled hybridization with a view to achieving specific results is not considered unacceptable by cactus lovers though some do not encourage it. Due to my views on the subject of hybridization as a fishkeeper I personally do not entirely agree with hybridizing plants. Having said that I have to admit that some “man made” Astrophytum are really outstanding specimens. The Japanese are masters at producing such excellent man made varieties. This as it may be, make sure that if you get plants these are in top notch condition. Plants in poor condition may never get to blossom and if they do their seeds will be of poor quality.
Once you get the seeds you must plant them. Pick carefully the time of the year to do so. Here, in Italy, I prefer planting the seeds in late spring or early summer. I believe this is the best period for planting as it allows for two, three or possibly more months of good/excellent weather in the first, delicate stage of their life. You can either use seeds of the previous season (I refer later on to keeping the seeds properly), late seeds or even seeds of the same season. In my view there is no universal rule on the type of seeds to use though generally speaking younger seeds tend to do better in that they produce seedlings with faster and better growth rate. Whichever type of seed you prefer please remember not to allow the seeds to age more than one or two years.
And here we have the seeds, lots of seeds. I spread them carefully on a dry surface to allow them to dry in the air, away from winds, of course. This is an important step in the process to prevent the seeds from moulding. You may wish to spread the seeds on a moisture absorbant piece of paper to help the drying process; I personally do not use drying paper.
The next thing to do is to get some plastic containers and / or pots. Get one container per each variety of seeds you are want to plant. Make sure you keep these well apart as seeds of different plants are almost impossible to distinguish once mixed up.
The photo above shows how I prepare for planting. A tidy environment is not a strict requirement but it helps a lot. A closer inspection shows empty containers (the transparent ones) in the background and half ready ones in the foreground (the green containers). The plastic film boxes on the right are now closed to prevent possible seed mixing: each one of these contains a different kind of seeds and is marked accordingly (indicating the genus, species, origin etc (e.g. wild or cultivated).
A closer look shows how the soil is prepared for planting: a layer of clay particles (you can find these in most garden centres) at the bottom is a must to allow for appropriate drainage. As clay retains water the bottom of each tray will remain wet (muddy) thus ensuring that the young plants have the moisture levels required for them to grow successfuly. Above the clay layer I have placed a good a quality soil layer. Avoid already fertilized soil to prevent too many nutrients; cacti do not need a lot of nutrients as they live in poor quality soils.
A little trick that I use is to place the soil, prior to planting the seeds, in the microwave oven (temp: 1000° C) for one or two minutes. This eradicates parasites such as insects eggs, larvae and / or other – unwanted – seeds in the soil. Make sure that the soil has properly cooled dwon (to environment temperature) prior to planting.
Once the clay/earth mix (separate layers) is in place I distribute the seeds randomly over the whole surface of the soil. You should end up with something like this:
And – even if the macro-shot is anything but perfect – in detail it will look like this:
In the photo above I have used red circles around the seeds and yellow circles around tiny stones in the soil. The seeds look quite similar to the little stones in colour, size and shape allowing, in the wild, the seeds to camouflage amongst the tiny stones thus protecting them from feeding birds.
It is now time to start the engine of life by watering the seeds. You need to supply your cactus-to-be with plenty of water (cool/room temperature will do). Since many seeds are extremely tiny and light you may consider watering them from the bottom of each container:
I can water my seeds from the bottom of each container by filling the base tray with water. The water sips through to the soil via the pre-drilled holes allowing the whole substrate to slowly soak completely. I always use this watering technique at the very beginning of the process to ensure that I do not disturb the seeds in the surface of the soil. For the technique to be successful it is imperative to have an adequate clay substrate at the bottom of each planting container. The clay will stop the water from flowing fast and will maintain a high rate of humidity available to the growing plantlets.
We are coming to the end of the planting process. The next thing to do is quite important and, in my view, the real key to success: we need to cover all the containers tightly and place them in a well lit and warm area, away from direct sunlight. Please make sure that there is enough air circulation inside the containers (i.e. these are closed tightly but not sealed airtight) to avoid mould settling in.
This concludes the planting process. Now that each and every group of seeds has been planted and the soil has been watered the only thing you need to do is to keep checking for levels of moisture inside all the containers. If you can see plenty of moisture (visible as water drops) set on the cling film or cover of each container things are going well: the humidity rate is correct and the seeds are on their way to developing correctly. Lack of moisture indicates it is time to supply more water, either using the bottom watering technique or by spraying lightly the top of the soil. If adequate amount of water has been provided initially through bottom watering I prefer to spray water in subseqent waterings; this method is less invasive for plantlets.
Your efforts are over at this stage. So what should you expect from now on?
This very much depends on the species of the plants you are trying to propagate. There are seeds that will begin their growth in days while others will take longer, weeks or even months. The growth rates are extremely different and depend on the genus / species. Even amongst conspecifics there will fast and slow growers as well as seeds that will not make it at all. This is life ... Allowing for the variations indicated you should eventually start noticing the seeds growing and the young plants appearing:
The photos above show three week old plantlets. Notice the highly watered substrate and the different germination and growth rate in the two photos. In this respect I should note that all “pure strain” plants of the genus Astrophytum will reward you with high germination rate and strong, easy growth; the commonly known “Bishop Cap” (A. myriostigma) is the undisputed genus champion!
Look after your plants as indicated at the beginning of this presentation and eventually you will come to this stage:
The plants in the photos above are three years old and have been individually potted (you must only do this when the plants are strong enough to be handled without damaging them. It is important to notice the following points:
- The soil is now dry (the way it is supposed to be for a cactus). Watering must be minimised once the plantlets turn into a “scale-down” image of parents while – even at this age – it is better to keep them away from direct sun light, mainly around noon time during hot summer days.
- The plants of the two groups shown above were planted at the same time and were looked after the same way: you do not need a hawk-eye to notice their different size and growth rate (the plants in the second photo are young A. myriostigma).
I will end my presentation by proudly presenting my seven year old juvenile Echinocactus plathiacanthus plants which I have grown, of course, from seeds. In the wild these plants will outgrow a human being; I have witnessed this while visiting the Huasteca region in San Luis Potosì state in Mexico during my first trip to the country. By the time it reaches such a size a plant will most likely be two hundred years old or so. Hence the one I saw was already thriving under the Mexican hot sun during the Mexican Revolution and has possibly witnessed the bravery of Emiliano Zapata and Pancho Villa!
Will you be patient enough to give your cacti the same chance? I do not know … but I have already begun my effort: roughly thirty of them are, as of June 2009, basking in the garden sun. I have no reason to hurry; do you?
Photos by the author.
Notes
1. To collect cacti seeds: after blossoming a plant - a cactus too - gives fruit, provided the flower has been fertilised naturally or artificially. In cacti the "lower part" of the flower (the one attached to the plant) will begin to grow larger and will eventually open up while the flower itself decays. This will allow seeds to scatter (mostly because of the wind). When the flower has decayed and the lower part (fruit) begins to crack up, genfly remove the fruit and allow it to dry a bit in a dark place. Once dried crush it gently and collect the seeds. Be very careful as many of these seeds are absolutely tiny. Store the seeds in a cool, dry, well areated place until you are ready to plant them. I use small card boxes to store the seeds. Plastic containers provide considerably less aeration and that is risky as the rooting may start using the humidity of the seeds themselves. Do not allow the seeds to age too much, plant as soon as possible after collection.
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