Growing cactus from seeds

Cactus seedlings are very fragile on the first weeks and survival depends on how they are treated on that crucial stage; out of 100 of seeds in the wild only a few survive to an adult plant to produce seeds and start the cycle again. Obtaining a high percentage of adult plants from a batch of seedlings, depends on how each collector takes care of their seedlings.It is not really hard to do once you follow a few steps--most importantly is to check the seedlings every day for at least the first 2 months.

Water for seedlings is the most important item to keep them growing for first few weeks. Generally, most seedlings, which are 1 week old will die after 3 days of dryness. 2 month-old seedlings can survive for 1 week if allowed to dry. 6 month-old seedlings can survive for 2 months if allowed to dry. 1 year-old seedlings can survive for 5 months if allowed to dry. As you can see, the dryness tolerance for seedling is minimal during their first days; thus the reason to keep checking them every day--seedlings need to be kept in a humid atmosphere for at least the first weeks. If any fungus or bacterial infection appears, remove the affected seedlings and treat with fungicide. At that time, it is better to avoid the cover but they must be sprayed every day until they are 2 months old. The best source of water is distilled, reverse osmosis or rainwater. Rainwater must be collected on an open container directly from the sky or during heavy rains avoid collecting rainwater during the first few minutes allowing time to clean the roof because roofs always collect bacteria from birds and insects. City water must be avoided because of chlorine and others chemicals.

Light is very important once the seeds begin to germinate; studies show seeds on any light condition (even dark) will germinate if keep in a humid atmosphere and ideal temperature but everything changes once they sprout. After germination, they need the right wave of light (color) in order to obtain good results. Perfect light is always sunlight filtered with shade cloths or poly cover. Also, under a tree avoiding direct sun but always protecting from rain; artificial light will work very well too if you choose the right color--plants or aquarium lights will be the best. My experience show the best for cactus and succulents seedling will be 10000K to 20000K; if fluorescent lights are used, they can be combined with 2 different colors (i.e. one from 6500K to 10000K and the other from 10000K to 20000K keeping as wide as possible the difference between the 2 colors. Together will produce a perfect wave of length to promote healthy growth). Every month you can adjust the light intensity because the seedlings will need to go little by little into a full sun in about one year. If you notice the seedlings are turning pink or red you may need to reduce the light intensity specially if under sunlight; be careful to make big steps on light intensity because it can damage the seedlings (even if they don’t die, they will show a horrible sunburn damage for life).

Air circulation: If the seedling are kept inside a house with air conditioning under artificial light or windowsill this will not be a problem. Even under a tree, most of the time, the conditions will be good for seedlings; but if the seedlings are kept in a greenhouse or enclosure, it is most important to keep them well ventilation. Air flow must be continuous to keep away the conditions that result in molds and/or fungus reproduction. To promote healthy growth on seedlings, a small fan can solve the problem; make sure the fan does not blow directly on the seedlings in order to avoid the soil drying too quickly.