How often should you fertilize succulents and cacti indoors vs the ones that are outdoors during growing season?

Klara333 said:How often should you fertilize succulents and cacti indoors vs the ones that are outdoors during growing season?

I very rarely fertilize. If I do it's only when there getting perfect sun light. Use a very low nitrogen fertilizer, one for succulents.

I have fertilizer for cacti and succulents with 4-6-8 NPK ratios, does that ratio sound alright?
On label it states to use fertilizer(diluted) every 15-20 days during spring and summer, which sounds like a lot to me, that's why I asked.

That sounds fine.

The frequency is related to the dose... you can feed every time you water (like me) if you use a really low dose of fertilizer and most of your plants are in full (outdoor) sun. Or you can feed once in a while with a slightly higher dose. The recommended amount is usually way more than your plants will ever need or enjoy. It seems to be calculated to maximize your consumption. Usually 1/4 or sometimes even 1/20 that amount is good for regular use.

If your plants are inside you might try feeding a few times a year, or not at all. If your plants are outside you can try feeding at every watering (during spring and summer) with 1 teaspoon/gallon (6ml/5 liters) of the stuff you have. You can save the leftover fertilizer water for future use (I try not to store it for much more than a week) if you keep it in a cool, dark place.

It is important to flush with a little excess water every time you water if you're going to be feeding your plants, so the dissolved salts don't build up in the soil.

I rarely fertilize as well. All of my plants are grown indoors. I have a liquid fertilizer for succulents that gets heavily diluted in water, and if I do fertilize, I just give it to them when they start actively growing in spring, and that's really it. The bottle recommends every few weeks, but I just do once in spring for a little boost. Unless the plants are being repotted with fresh soil, then I don't bother.

Thanks for the detailed instructions, I really appreciate it.

@Klara333 great question
hello all
Please educate me, what would be the effect of too much fertiliser indoors? Is it right that the lower the soil concentration of your mix the less nutrients can be provided by the soil and you should fertilise more? Should you fertilise more if you use rainwater than tap? I have a small aquarium on which i change water every week. This used water it likely to contain higher nitrates is this a good thing for cacti or bad?
Steve

I couldn't say what the specific effects of overfeeding indoors might be (I've never done it) but I would imagine there could be some stretching involved, especially with low light. When in doubt with fertilizer, start low and see what the results are, then adjust as necessary from there on out. That would be the most economic route.

A reasonably high percentage of composted organic matter in the soil will make it unnecessary to fertilize until years have passed and it has begun turning to dust. Any recently repotted plant does not need fertilizer, since the new compost is full of nutrients. Some people never fertilize but they get better results with periodic soil replacement (after 1-2 years) for some plants. I feed at every watering because I refuse to go the soil replacement route (out of laziness), and some of my plants have been in the same pots for a decade or more.

I don't think the amount of fertilizer would be different with rainwater vs. tap water. I use the same amount with purified (RO plus) water and our salty tap water.

The aquarium water ought to be great for your plants. Other folks on this forum have reported good results using that.

@baja
thanks for your comments.
i guess this one of those areas where a lot of different approaches seem to work so there is going to be no specific answer. As you know I have mainly aloes now in my collection and i guess my earliest plants are maybe 2 years in the same pot. I am reluctant to repot (as this often seems to upset aloes) but i am concerned there may be limited nutrients in the pot as i started with such a gritty mix. I use rainwater at the moment so the PH is likely to be low with little if any dissolved trace mineral elements (which get into the water from it running through rocks in hard water areas). A lot of aloes live in rocky soils or even on rock faces so you would imagine that the water these plants receive in habitat contain mineral elements ? (i guess the plants could get the same from our substrates dependant on what is used). i am trying to decide if my best approach is to dose with fertiliser at a low level (as you do) or repot /refresh soil mixes every few years..
Steve

I haven't used aquarium water for my cactuses/succulents, but I've used it for orchids with good results. However, I used water closer to the tops of my aquariums, so it wouldn't have been as high in waste materials and nitrates.