Cacti require little water and few nutrients to grow and thrive. A standard potting soil retains too much moisture, which can cause the cactus roots to rot. Most potting soils also come with nutrients added in the form of compost or fertilizers, negatively impacting the cactus.
Making your own soil mixture ensures the plants receive the proper drainage necessary for healthy growth. The type of cactus soil needed depends on whether you are potting a tropical Holiday Cactus, which tolerates more moisture, or a desert cactus that needs a drier soil.
- Combine equal parts peat moss and ground fir bark in a bucket to create a base potting mixture for tropical or desert cacti. Alternatively, use a premade potting mix that does not contain soil. Peat moss is not a problem as long as you are careful of how much water you give your cacti. Potting soil with peat moss tends to retain too much water to keep cacti healthy and thriving.
- Mix two parts of the potting base mix with one part coarse builder's sand for a tropical or Holiday Cactus, which requires more moisture and tolerates less drainage than desert cacti. Substitute perlite, pumice, or vermiculite, if desired.
- Use equal parts of the base potting mix and coarse sand, perlite, pumice, or vermiculite for a desert cactus, as they cannot tolerate too much moisture retention and grow better in a sandy, well-drained mixture.
- Mix the ingredients until they are completely combined. Break up any large clods that form, so the potting mix is evenly blended.
- Water the mixture in the bucket before filling the pots and planting the cactus. Allow the peat or coir in the mix to absorb the water for at least one hour. Use for potting when the mixture feels moist, but no water droplets form if you squeeze a handful.
Cactus plants have low nutrient requirements, so there is no need to add fertilizers to the potting mix. Instead, fertilize the plants sparingly with a soluble cactus fertilizer every three to four months.
Over-watering can quickly kill a cactus. Place the soil only in pots that contain drainage holes to allow excess moisture to drip from the pot—water most cacti only when the soil has almost completely dried.
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What is potting soil?
Before I introduce my favorite DIY potting soil recipes, let’s talk about what potting soil actually is. The most important thing to understand about potting soil is that it doesn’t actually contain real soil. Potting soil, also called potting mix, is a soilless blend of ingredients used to grow plants. Whether you’re starting seeds, rooting cuttings, potting up houseplants, or growing patio containers and hanging baskets, potting soil is the ideal growing medium for containerized plants. All good-quality potting mixes, including homemade potting soils, have a few things in common.
- They’re better draining than the average garden soil.
- Potting soil is more lightweight than garden soil.
- It’s easy to handle and consistent.
Like commercial potting soils, you can make many different DIY potting soil blends, each with a different texture, nutritional content, density, and water-holding capacity, all matched to the needs of your plants. Carefully select the ingredients you use and combine them in the correct ratios to tailor each DIY potting soil you make for the specific needs of each plant you’re growing.
- Lighter, finer-textured mixes are best for use when starting seeds and rooting cuttings.
- Mixes containing a high percentage of coarse sand or pine bark are best for potted trees and shrubs.
- DIY potting soil with a sandy or gravely texture is ideal for cactus and succulent growing.
- When growing a mixture of annuals, perennials, vegetables, and tropicals, the best fit is a general, all-purpose potting mix – one that’s suitable for growing lots of different kinds of plants.
There are dozens of specialized potting soil mixes you can make.
How to Water a Cactus
To avoid over-watering your cactus, only water it when soil completely dries out
Water cactus plants by thoroughly soaking the soil. Allow all the excess water to drip out the bottom of the pot. Only water the cactus as often as the potting mix completely dries out. In summer, you may have to water a cactus as often as every week.
Cacti are drought-tolerant plants, and they hate over-watering. So, let soil dryness be your guide to watering the plants. The room temperature, sunshine, humidity, season, and type of cactus can affect how often you need to water cactus plants. Avoid the mistake of watering on a set schedule.
Generally, you need to water a cactus every seven to fourteen days in summer. During winter, your cactus plant can go for many weeks without water. Remember that cacti store moisture in their succulent leaves. It’s best to err on the side of caution and water cactus plants less often rather than too much.
To make your own cactus soil, you will need a few ingredients discussed below. You can purchase most of these ingredients from your local plant or home improvement store.
1. Regular potting soil
Any type of regular potting soil will work fine as the base to prepare your own cactus mix. Feel free to use whatever you have at hand as long as it is fresh and sterile potting soil.
If you can get light, porous soil to use as the base, it will be great because that will make your work pretty easy. Avoid using heavy garden soils or potting soils that contain vermiculite or any other moisture control elements that helps the soil retain moisture for prolonged periods.
Keep in mind that your cacti plants require well-draining soil, not one that retains moisture for too long. Therefore, you need to be careful when choosing a type of potting soil as the base because it will determine the outcome.
2. Coarse sand
Cacti plants thrive in a porous sandy potting mix. So, adding some coarse sand to your regular potting soil is critical. Feel free to use any type of sand but ensure you achieve good drainage at the end. Consider purchasing coarse sand other than the fine stuff you might come across in your compound.
Don’t use sand from your garden, beach, or a traditional sandbox. That type of sand is not good enough, and it won’t help you achieve better results.
If you prefer, you can use poultry grit or turface instead of sand. Either of those serves as an excellent alternative to coarse sand in this recipe.
Perlite is a lightweight organic soil addition. It is the white pieces that resemble Styrofoam that you see in commercial potting soils. The primary purpose of perlite is to prevent soil compaction and enhance the aeration. It also improves the drainage of your cactus soil.
In other words, perlite helps your soil drain faster, which is precisely what you are looking for in good soil. You can purchase perlite and pumice at your local plant/home improvement store. It is usually in the same section as commercial potting mix for sale.
If you cannot find it in your local home improvement store, buy it online.
You need to ensure your soil has the right pH level. Sometimes, you may prepare your cactus soil and discover that the pH level is pretty high. To lower the pH level, add a small portion of peat to your recipe. However, you should keep in mind that this component can make it difficult to re-wet the soil.
5. Gravel/lava rocks
Gravel and lava rocks are another decent addition to your cactus soil recipe. They are coarse and will help make the potting mix loose and airy.
6. Charcoal & coir
Charcoal is one of the best air conditioners you can use in your DIY cactus soil recipe. It helps prevent diseases by absorbing impurities and ensuring the harmful microorganisms don’t attack the roots of your plants.
Coir helps to retain small amounts of moisture in the soil and also provides a non-compact structure. Some people use coir to replace peat moss.
Apart from the ingredients, you will also need other supplies to make your own potting soil. They include:
- Measuring container/cup.
- A container for mixing (you can use a bucket or tabletop potting tray for this purpose).
- Trowel (a small shovel).
- Gardening gloves.
Cactus Potting Soil – Proper Planting Mix For Cacti Plants Indoors
Cacti are some of my favorite types of plants to grow inside all year and outside in summer. Unfortunately, the ambient air tends to stay moist during most seasons, a condition which makes cacti unhappy. Cactus potting soil can enhance drainage, increase evaporation and provide the dry conditions that cacti favor. What is cactus mix? This medium promotes optimum health for your cactus and mimics the natural gritty, arid and low nutrient soils they grow in naturally. You can purchase the mixture or learn how to make cactus soil yourself.