By Marina Welham
Is your succulent collection a hospital of plants you play nurse to every day? Are you frequently tossing out plants that just won’t grow for you? Are you tired of seeing flowering plants in books and journals and other collections while your same plants sit there doing nothing from one season to the next? You can probably change all this dramatically if you will only FEED your plants.
Nature takes care of succulents in habitat. Plants grow only where they have their basic needs met. Bird and animal droppings fertilize the soil. Leaves and other material break down into compost enriching the soil. Even rocky locations provide something for plants growing there.
Many cacti thrive in gravelly areas where the rocky terrain, reacting to high heat, water, and some soil breakdown, provide micronutrients for the plants. Nature does not take care of these plants in pots! If you don’t feed your plants, they are going to be sick, sicker and eventually dead. A starving plant will usually not flower.
Succulents need food not only to help them grow and to flower, but also because a well-fed plant can fight off pests and diseases far better than a sickly one.
When plants are newly potted into fresh potting mix, they begin to use up the nutrients in the soil and some of those nutrients are washed out through the soil every time the plants are watered. When the goodness of the soil has been spent, the plants starve. The smaller the pot, the faster the soil is spent. This depletion of nutrients can be dealt with in two ways. You repot small plants annually into a fresh soil mix. Larger plants, difficult to repot too often, should have their top few inches of soil replaced with fresh soil and they should be religiously fertilized during their growing season which can be, depending on the plants, either in spring and summer or fall and winter. While this is an option for heavy, hard-to-handle large plants, there still comes a time when they, too, must be potted into fresh soil mix if they are to do well in the long run. There is no such thing as a healthy, happy plant that has been sitting in the same pot and the same soil for years on end.
The very best way to feed your plants is to use a potting mix that contains compost. Sometimes you can buy this ready made and then add soil, grit or sand or whatever other product you use to make the soil well draining. Compost helps retain nutrients for a longer time than soil without it.
Chemical fertilizers have their place, since some people simply do not have access to natural organic compost. These prepared fertilizers are made for basic agricultural or kitchen garden use. They are too strong for most succulents. That is why we always advise diluting them to one quarter of the strength recommended by the manufacturer. Succulents are much slower-growing plants than are the roses and dahlias in your garden. Roses and dahlias need lots of nitrogen to help them grow. Succulents not only do not need high nitrogen, they will suffer and even die if the dose is repeatedly too high.
A balanced fertilizer such as 20-20-20 mixed at 1/4 strength is best. Make sure the fertilizer has trace elements. Sometimes, regardless of all our care, our plants get sick and we wonder why. Very often, the problem can be due to the lack of one or more trace elements in the soil. Unless you are a chemist and know how to determine which element(s) the plants are missing … just make sure trace elements are included in the fertilizer you are using.
To encourage a plant to put out a little extra oomph at flowering time, a couple of shots of 20-30-20 or any fertilizer with a higher middle number (phosphorus), again at 1/4 strength, should do the trick. After flowering, go back to using your regular balanced fertilizer (20-20-20) at quarter strength.
What about those slow release fertilizers on the market? Most are activated every time you water the soil. Some are activated by both heat and water. If this is confusing to you, think how the plants must feel about this kind of feeding schedule! At the very least, this ‘automatic’ burst of food can be too much for small pots that may need watering every day or two. Using a liquid fertilizer that can be well mixed with water and applied when you know the plant should have it, is far safer to use. The one exception is bone meal, which is quite safe to add to the soil in very small quantities. It has a very low nitrogen content and works in the soil over a long period of time.
Everybody (seems like) wants to know if Cactus Juice is okay to use. Yes it is because its primary claim to fame is its low nitrogen content which is important for many cacti. Is it wise, however, to use Cactus Juice which is not a balanced fertilizer with trace elements? Why would you pay more for that product in a tiny bottle when you can buy a way bigger bottle of another well balanced fertilizer that has all the important trace elements-at around the same price?
While following the rules of feeding succulents, we also have to use a little common sense. For example, would you think that the feeding given a cactus the size of a button would be enough for a 6 ft., vigorously growing, columnar type cactus? Of course not. Depending on the size of the plant and how fast it grows, you might decide, and rightly so, to give the larger plant a stronger than 1/4 strength feeding a couple of times during the growing season.
For many years, I followed the low nitrogen rule with all my cacti. One day, while sitting there wondering why my opuntias in 5-gallon and larger pots were not flowering, and in fact had not been growing much for quite some time, I had an epiphany. If they were all reacting like lazy boarders, was it because they were not being fed enough? The only way to find out was to experiment. I first gave them a good watering with a half strength dose of a balanced fertilizer with trace elements. I waited two weeks and gave them another and two weeks after that gave them a full strength dose. Those cacti must have been starving. They began to grow, put on new pads and three of them produced beautiful flowers that same year. After that, I watered and fed them only when the soil had almost dried out and regularly gave them a half-strength feed. I did not start this experiment with a full-strength feed because I didn’t want to burn the roots which had not been accustomed to such a strong feed in the past.
The organic fertilizer known as fish emulsion is high in nitrate and contains some trace elements. It is somewhat on the acid side, so for plants not liking acid, it should not be used. In addition, prolonged use can cause the roots of plants to burn.
Just as important as not feeding plants enough is over-feeding them. You won’t make plants grow or flower any faster (unless they are already starving). They will just become weak and lush and open to all sorts of pests and disease problems.
Burned or dried leaf margins and wilted plants often are a sign of excess fertilizer, which problems are sometimes misdiagnosed as too much sun and not enough water.
Plants need less feeding or none at all under low light conditions. If there is a long stretch of lousy weather when it rains and pours and sun is a fleeting luxury … do not feed your plants.
Succulents should never be fed if they are not growing or are looking poorly.
Fertilizer should be added to moist, not dry soil. Otherwise the solution comes into direct contact with the roots and they can be burned. Always moisten the soil with plain water first and then give a second watering after a few hours with the liquid fertilizer added.
Please read the article on our web site about the importance of soil pH because this is very important. If the pH of the soil is wrong, feeding is useless, as the plants will not be using the fertilizer to best advantage.
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