Cactuses, or cacti, are rather slow growers and can take years to show significant growth. But if you want your cacti to grow faster, is there anything you can do? In this post, you will find tips on how to make your cacti grow faster and general care tips to make them flourish.
To make cacti grow faster, you need to have a consistent watering schedule, allow proper air exchange, use soft water for watering. Also, fertilize your cacti during growth period and allow cacti to go dormant during cold period.
Tip 1: Allow your cacti to go dormant in winter
Cactuses in their natural environment actually go dormant in high summer heat, when there’s lack of water. During summer, they stop growing, but concentrate on surviving high temperatures and transpiration (water evaporation from the plant).
Please do not make your cactus grow year round to see quicker growth. That’s one of the main mistakes that cacti owners make. Not allowing cacti go dormant in winter will cause thinning and elongated growth and weakening of a cactus.
If you are keeping your cactus at home and have cold winters, you need to allow your cactus go dormant in winter. This will prevent an uneven growth, depletion of nutrients. Winter dormancy will also help your cactus form flower buds (if flowering or starting to flower).
To allow your cacti to have a dormancy period, you need to mimic the period of lack of sunlight. When temperatures outdoors start lowering (towards mid October), you need to gradually decrease watering.
However, the most important bit – don’t stop watering altogether. While some owners advice not to water cacti at all in winter, they need some water to stay healthy.
If you don’t water your cacti in winter, it will lose roots, dry out and experience stunted growth later. Watering lightly around once a month to once 5-6 weeks during dormant period might be sufficient (check the soil first).
In November up until beginning of March, you need to keep your cactus in a cool area. Temperatures should be around 47-54 F (8-12 C), and this is crucial. Lower temperatures will prevent excessive water evaporation, and continued growth.
#2: Provide enough sunlight during growth period
To allow your cactus to grow, you will need to provide it with enough sunlight. While scorching heat in their natural habitat makes them go dormant, you will need to provide enough sunlight to your cactus to grow in summer. This is provided you have warm-hot summers and cool/cold winters.
Most cacti, especially desert cacti, require lots of bright light. Tropical cacti prefer indirect, but bright light. Both types need lots of bright and mostly indirect light. In summer, you can keep your cacti on a windowsill, balcony or even outside.
However, high mid-day heat can burn your cacti. Outdoors, it’s often fine, but behind a glass, temperatures can have a burning effect. Don’t also allow your cacti to stay in a spot with direct sunlight for more than couple of hours, especially in high heat. That will vary with species though.
Another important thing to remember that cacti in their natural habitats gets used to constant high heat and sun, but at home, they are not used to it. Especially after winter dormancy, you must gradually introduce them to sun, avoid burns that can even kill cacti.
If you mist cacti, do it very early in the morning before sun is up, or after sun has set. That’s because the spines will be minimally hot, to help evaporate the water. During high heat, do not mist your cacti, as water will act as a lens and can cause burns.
To summarize this point, cacti needs lots of bright (sometimes shaded light) to grow. Do not put your cactus on a shelf or low lit bathroom (unless it is tolerant of low light). This way, your cactus won’t grow and will slowly die.
South-east and south-west facing windowsills are the best for positioning most cacti species. On south facing windowsills, you might need to shade cacti during peak hours. If you have desert or tropical cacti that prefer filtered/shaded light, west and northwest facing windowsills are optimal.
#3: Allow proper air exchange
Cacti love good air exchange and cannot thrive without it. They hate high humidity, stagnant air and will slowly die if living in those conditions. Having said that, avoid any drafts and placing cacti under air conditioning – they hate sudden temperature fluctuations. Don’t place by radiators in winter – put in a cool location.
When keeping cacti at home, make sure to place them in a bright spot such as balcony, windowsill or even outdoors. Avoid putting cacti in closed terrariums – they cannot survive high humidity.
In summer, you can even leave your cacti outside if possible – fresh air will only help them grow. However, if temperatures where you live drop very low during summer nights (lower than 55F, or 13 Celsius), never water your plants in evenings. Take them indoors in this case.
If temperatures at night are low and then get very high, misting with hot water or watering in the morning great to mimic morning dew. Daytime summer temperatures of around 80-86 F (27-30 Celsius) are ideal for most cacti.
If using cacti for a terrarium, try to do it only temporarily, for few days. That’s because cacti will have trouble absorbing water in a glass container. Terrariums also lack drainage holes and have layers of soil, rocks and charcoal, making it hard for cacti to absorb water.
You can read more about the best containers for cacti here.
#4: Perform a watering trick
Once in a while, you can perform a ‘hot bath/greenhouse’ watering trick with your cacti. This watering method can be performed occasionally (1-2 times a month depending on often you water cacti) during the growth period. It will mimic natural humid conditions and promote growth and flowering.
For this watering trick, water your cacti before sun is up (you can also mist it a little). Then, cover it with a plastic cloche or another cover. Once sun starts hitting your cactus, it will increase humidity inside the cover, mimicking hot and rainy summer weather.
Keep it on for around 1 hour, and then slowly start opening the cover. Don’t do it suddenly, as temperature difference will be too sudden.
When watering your cacti, make sure to only use warm water of around 86-104 degrees F (30-40 degrees C). When misting, use hot water, as water temperature drops significantly and suddenly after you mist the plant.
#5: Avoid repotting or separating pups from flowering cacti
If you don’t want to hinder your cacti’s growth and prevent it from flowering, don’t repot it during flowering. If you repot flowering cacti, its flowers will fall off, or it will stop flowering altogether.
What is more, you should not separate pups from a flowering parent cactus – this will interfere with plant’s normal growth process. Both repotting and separating pups from a growing and flowering cactus will disturb its growth.
The best time to repot your cactus is just before the growth season starts, by the end of dormancy.
#6: Use soft water to water your cacti
You must always aim to water your cacti with soft water. Soft water has lower content of minerals, which cacti are very sensitive to. Those minerals accumulate in soil and reach very high levels. This interferes with cactus growth and even causes root death.
The best type of water to use for watering cacti are rainwater, distilled water, bottled, reverse-osmosis water. You can also check how pure water is by using a TDS meter like this, and you should aim for up to 150ppm for cacti.
If your only option is tap water, make sure to leave it outside in an open dish for 1-2 hours before watering your cacti. Also, you will need to repot your cacti often if using hard water – otherwise it will stunt your cacti growth.
If using tap water, repot your cactus every 1-1.5 years or so, as opposed to every 2-3 years when using soft water. You can learn more about watering cactuses in this post.
#7: Fertilize your cacti
You can fertilize your cacti to help them with flowering and to grow faster. However, you must take care with fertilization, and don’t fertilize dormant cacti. Only fertilize cacti during growth season.
Slow-release fertilizer is the best type for cacti. It will feed cacti for a longer period of time, sometimes up to 4-6 months. Bone-meal like this or egg shells added to the bottom of the container will act as a fertilizer. It will slowly release nutrients without shocking cacti and will mimic natural fertilization in their natural environment.
Another option is to use a liquid fertilizer, that you dissolve in water and use when watering cacti. Choose a lower nitrogen, higher potassium fertilizer like this. During growth season in summer, mix in water and use as directed.
#8: Repot your cactus once in a while
Repotting your cacti is very important once in a while, to promote healthy growth and keep your plant alive. Not only it is beneficial, but also necessary. Old soil accumulates excess minerals from water as well as unused fertilizer. Also, cacti grow and overtime, need more space for their roots.
How often you need to repot your cactus will depend on which water you use and whether your cacti have overgrown its current container. You will need to take it out and have a look at roots (roots might also be sticking out). If you use tap water to water your cacti, repot every 12-18 months, and the rest – every 2-3 years or so.
When you repot your cacti, it will give them a new fresh start for better growth. You can add a slow-release fertilizer in the soil to promote better growth too. Also, wash and disinfect all containers before using. All containers must have drainage holes.
When repotting, be careful with roots. You must only repot into dry soil and wait 7-10 days before you water your cacti after repotting. This will allow roots to heal before taking in water, thus preventing infections.
Keep cacti away from strong sun just after repotting until you water your cactus again. Make sure not to pot your cactus in a large container, otherwise it won’t be able to absorb necessary water.
A comfortable container for your cactus should have few inches to each side and some extra depth, but nothing too large. Place the plant at the same height, to allow new space to be used for root growth.