Can I just use a soil that is 1/2 sand and 1/2 potting mix with a little lime and bone meal to grow epi seeds?
Can you use normal cactus soil to germinate epi seeds
Hi Hayu,
I see nobody has answered this so I will have a go. I plant all of my cacti seeds in a mix of my own devising, including the epiphytic kinds. I use 50% sharp sand (extra gritty sand) and 50% sieved leaf mould or compost, no fertilisers. It seems to me that everyone has a different take on this, so seed raising mixtures come in infinite varieties (one for each gardener, LOL!) The ingredients themselves are not as critical as the physical properties - what you want is a mix which will hold a little moisture without being sopping wet, and one where the water drains through freely, leaving the mix just damp. Commercial potting mix is far too rich, you would probably need to use about 20% potting mix and 80 % sand.
The next thing which is important is that the mix and any water used to moisten it MUST be sterilised. I used to do this in the kitchen oven, but now I do small batches in the microwave as I need it which is much more convenient. The reason for this is that most cacti seeds are quite small, and the seedlings grow relatively slowly, especially at the beginning. If you think about the germinating seed for a bit, initially it contains everything the plant needs to start to grow except for water and the gases of respiration. Many types of seed do not even need light for energy, in fact some seeds will NOT germinate if exposed to light, fortunately it doesn't seem to bother cacti. So the seed soaks up water, it swells up, the coat splits and it puts forth a root, allowing it to soak up more water, and hold itself to the ground. Next the seed uses its stored reserves to start to make the plant's stem and leaves, chlorophyll appears and away it goes. It isn't until this point that the seedling can make use of any external chemicals from it's environment so it has little need for fertilisers at the beginning. Cacti, in particular are not fond of excess food at any time, since they are adapted to environments where scarcity is the norm rather than the exception. Once the seedlings are a good size, you will probably have pot them up any way or they will crowd each other, and that is the time to start to add fertiliser to their soil mix.
However, potting mixes, garden soils, and composts are full of living organisms which can make use of the nutrients in such things - algae, bacteria and fungi! all of which will grow in your pots and smother your cacti seedlings long before they get big enough to compete successfully. Heat treating your seedling mix will cut down the numbers of these simple organisms and give your seedlings the chance to get ahead. I usually put my pots of seeds inside a plastic freezer bag dampen them and then seal the top of the bag up and do my best to ignore them for at least a couple of months. As long as the bag stays shut you should maintain a clean environment for the seeds. Stand the bags in a lighted area but not in direct sun, and check to make sure they don't dry out - if they get too dry looking, add a little more sterile water.
Once the seedlings are about an inch or so tall, you can gradually open the bag and then take it off completely, really by this time, the plants will be big enough to handle safely so you can pot them out into a more normal mixture and grow them on. Best of luck, KK.
Thanks! I have them in a soil mixture of 2/3 cement sand( I don't know if that is sharp or not. The builders will let me have whats left over for free) and 1/3 peat. I zapped the mixture in the microwave. I don't have leaf mold, none of the stores have that so I went with peat. I bought 15 seeds and 17 came up. :) I spray them almost every day since they are outside in a plastic seed tray. They receive morning sun maybe 2hrs or less.
Hi Hayu,
It seems you must be doing something right if you have 2 more seedlings than you planted seeds LOL!, Peat is OK in those proportions, but it's not one of my favourite ingredients. The light exposure sounds good as well, just keep an eye on them as the summer advances, as the tiny plants will be much more sun sensitive than adult plants. Since you now have seedlings, I am sure I echo the rest of the forum in saying we want to see pictures! By the way, don't freak out, but the first growth between the seedling leaves won't look much like an Epiphyllum stem; they actually start out as little bristly cylinders and assume the normal flattened form as they mature.
Ciao, KK.