Q&A for How to Grow Cactus Indoors

Reduce your watering to once a month or even once every other month, depending on the humidity level in your house. Let the soil dry out completely between waterings.

You do not need to put the Christmas cactus in a dark closet for it to have a dormancy period. Reduce watering and fertilizing. Placing the cactus in a cooler window will assist with dormancy.

The best fertilizer for your indoor cactus is a balanced one, to ensure that all the nutrients needed are provided. The ratios of nitrogen, potassium and phosphorus will depend on what you want the plant to achieve: growth (higher nitrogen ratio), more flowering (higher potassium ratio) or greater disease resistance (higher phosphorus ratio). Use liquid fertilizer, it should be at a quarter to half strength, as cacti are not heavy feeders; apply during watering when it’s the growing season. If the cactus is receiving little light indoors, do not give it too much fertilizer or it will produce weak growth.

Most cacti need the soil to almost dry out before receiving their next watering, so weekly or biweekly watering is often appropriate. Many garden and potted cacti suffer from over-watering but it is also possible to let the soil dry out too much if the cactus is left unwatered a long time, especially with potted varieties. To know how much water to give a cactus, check the soil: if it’s moist, don’t water but if it’s dry or nearly dry, it’s time to water. Cacti need less water during winter, dormancy or cold/wet weather and need more water during the growing season. Water early morning, to allow the day’s warmth to dry off any excess water on the spikes and crevices of the cactus.

There are some species of cacti that are fine with low light, and these are probably a good choice for your situation. Some species worth considering for this purpose include: Rebutia and Scarlet Ball Cactus. Moreover, since you’ve said there is still sunlight, you can probably grow quite a few other cacti suited to indoor environments, and they’ll appreciate not risking sunburn from direct sunlight through a window.

Try putting the pot on a high and stable shelf or top of a wardrobe that you can reach but the children and pets cannot; use a stepping stool to water it if needed. If the cactus can go outdoors, fence it off somewhere in your garden; fencing off can produce various benefits, such as avoiding injuries on the spines, allowing specific soil amendments suited to cacti and ensuring that the lawnmower doesn’t accidentally chop it.

If the glass has no hole at the base to allow the water to drain out, this will not work for the cactus. A cactus needs free-draining soil that is moist when watered but dries out over the days and weeks after water. Too much water in the soil can cause the cactus to rot. Also, if the glass is placed in front of direct sunlight through a window, there is a risk of too much sunlight hitting the small area of soil through the transparent glass and overheating the cactus, which can kill it given that the cactus has so little soil to protect its roots. It would be better to use an opaque container with drainage.

Yes, you can grow prickly pear cactus indoors. You need to provide it with a full day of sunshine though, so position it at a window where it gets direct sunshine for most of the day. Use potting soil that drains well and only water about every 2 to 3 weeks, making the soil moist, not wet. This cactus loves heat, so try to give it a warm environment as much as possible (although cold nights are fine). If the plant gets too wet or cold, it may grow fungus, so use a fungicide if needed. For blooms, you’ll need to fertilize the plant biannually. If possible, take the plant outside during the warmer months.

Usually the spent flowers will fall off on their own and you don’t need to remove them. Some exceptions may be where the flower gets stuck in the cactus spines or it doesn’t fall off but looks as if it is starting to rot. In each case, removal with long-stemmed tweezers would be helpful for preventing rot or disease. Also remove flowers that land in the soil of a potted cactus, to avoid creating an environment for growing fungus when watered; this may not be an issue outdoors provided the weather is warm. Spent fruit should be removed as it can cause the plant to rot if left in place.

Some cacti need a lot of sunlight, while others will happily grow indoors without sun provided they have a good source of light. Too much sunlight can be just as bad as too little for some species of cacti; sunburned cacti will display bleaching on the side of the plant exposed to sunshine, which can become a scar. Both shade-loving cacti and even sun-loving cacti that has spent most of its life growing in shade but then gets moved into the sunlight too quickly can be damaged from too much sunlight. It’s important to learn the requirements for the cactus species you wish to grow, then choose its indoor or outdoor positions accordingly.

Many cacti species marketed for home growing are fairly easy to care for but don’t be fooled by their hardiness; they still need attention and care. Broadly, the needs of a cactus involve providing the right conditions -- sufficient light, temperatures between 5ºC-40ºC (40-104ºF), weekly watering but also accounting for dormancy and growth periods, and suitable fertilizer. Cacti also need regular pest, disease and rot checks, to ensure their ongoing health. For full details on cactus care, see How to Care for a Cactus .

Indoor cacti have to contend with a less optimal environment than their outdoor cousins. The reduced light, different heat, lack of rainwater, varying humidity, etc., can cause indoor cacti to mature much more slowly. Indoor cacti can be prone to rot, disease or pest infestations and may be burned from the sun through a too-hot window placement. All of these things can stunt the growth of the indoor cactus. Try shifting the cactus to a different spot, depending on what you think it might be missing out on.

Repot your cactus in new, dry soil. Water it every three weeks and give it a lot of sunlight.

On a windowsill that will access plenty of light. When moving the cactus, move it gradually, so as to avoid scorching.

Get a pot that has a drainage hole at the bottom. Cacti need adequate drainage. If the pot doesn't have a drain hole, the soil will become waterlogged and lead to root rot, which can kill your cactus.

It's too little, because too much water would make it store that water, and the arms would grow outwards.

Use one cup of water every three weeks and make sure it drains out of the bottom, so there is no damage to the roots of the cactus.

This is normal for cacti to do, and there are solutions. One way you could fix your cactus being yellow is to give it less water. Remember that cacti originally come from the desert, where they get little water. Secondly, try giving it fertilizer suited for cacti. Last but not least, change the soil -- they don't need black nutrient rich soil -- they need sand, gravel or rocky soil. These solutions should help your cactus/cacti in need.

Yes, cacti do need adequate drainage. Remember that cacti come from the desert and live in sand, which does not hold water well. So, they need drainage as they'd have in their natural habitat. If you do not have adequate drainage, your cactus/cacti will start to turn yellow and slowly turn a weird brown, then die. Drainage pots can be bought at any store that has a plant section. Also use the proper potting medium to ensure great drainage.

Yes, that is called propagation. It's best to propagate using new growths on the cactus.

Fill the pot with potting soil and water it thoroughly and using a spoon, make a hole in the soil. Place the snip of Christmas cactus in the hole about 1 inch (2.5cm) deep and scoop soil around it and press it down gently. Keep it moist and it will start rooting.

Purchase a cactus from a specialized shop which sells different types of plants and not from street sellers. This will ensure that you will get a high quality, resistant cactus.

Fish has been used as a plant fertilizer for centuries to impart nitrogen and trace minerals to the soil. However, in a pot with limited soil, you may be able to smell it.

Yes. Make sure you're using a soil that will drain well, such as crushed lava rock, sand, etc. Let the substrate dry out between waterings and give plenty of sunlight, and you will grow them easily.

There is no need to move it unless it is too big for the pot. Increase the pot size by two inches when it is time.

Cacti grow in the desert and have spines for protection, while succulents are smooth and grow in tropical areas. However, they are the same in numerous ways; for example, they both store water.

Typically if the temperature gets below 60 degrees F, the plant will go dormant. They don't handle anything below 50 degrees F very well.

Try repotting the cactus in a bigger bowl, and make sure it's deep enough that your cactus can fit with extra space in the bottom for the roots.

The best way to plant a cactus without getting pricked is to use strong kitchen roll. Depending on the width of your cactus, use 1-2 sheets and fold it length ways until you have a long, thick strip of kitchen roll. Gently place the strip around the cactus near the base and pinch the two ends together close to the plant. The kitchen roll will grip onto the spines and then you can tip the pot on its side and gently pull the cactus from the current pot and place it in the new one. (You can also use garden gloves but this tends to damage spines.)

It sounds like it's being watered too much. Make sure the soil has a chance to dry out completely between waterings. You could try repotting it in dry soil, and do not water for a couple of weeks.