Some gardeners prefer using pot to grow their plants. Sometimes it’s a space issue, sometimes it’s just a personal preference. Whatever the reason for pots, It’s obvious that the question of the best soil to fill the pots is going to come up.
So to help you fill up your pots with the best growing medium for your plants here’s a quick overview of some of the different types you can use.
Let’s start with the most common – potting mix. This is a special type of soil which is most commonly sold in a store, in a plastic bag. You can buy it in bulk from nursery supply stores as well, but trust me, you’re going to need a whole lot of pots to make a bulk purchase worthwhile.
So obviously its name gives us a pretty good indication of what we’re getting. These mixes are designed specifically for potting. They’ve got a good blend of nutrients required by a newly potted plant, as well as good soil conditioners and micro-organisms.
The mix of particles is pretty free draining, which suits pots that have only small drainage holes, but this means that they don’t hold water very well, and will need consistent watering. Despite that, it really is the best option, fitting the needs of most home gardeners.
You can also get special mixes that can be suited to growing specific types of plants (like Australian native, orchids, or fruit and veggies) that might have unique soil condition requirements, like pH, nutrient content, or drainage. You also get the bonus of it being pasteurised during its creation, generally meaning no weed seeds, or disease and viruses.
Garden soil is another option for your pots. If you don’t want to spend your money on a special potting mix, you can just dig up soil for your pots from the ground. It’s more hard work, but it can be an ok alternative, if you pick the right type for your plants.
The biggest issues with using straight garden soil in pots is the make up of the soil you use. Heavy clay soils will turn to rock in a pot, and will get compact and water logged really quickly through the limited drainage in pots. If you’re going down this path to save money, consider mixing ground soil with some humus, or, with some potting mix (going half/half will still save you money). This will give you better air circulation and water flow, as well as added nutrients and organic matter.
Secondly, you may transfer pest and disease from the soil in your garden into your pots. Things present in your garden soil might not be an issue for the plants in the ground, but that might not be so for any new plants you pot up. You also could improve the conditions for soil-borne plant diseases by placing pots in sunnier or wetter locations, causing the disease to thrive, or sometimes you can create competition in your pots through germinating dormant weed seeds in the garden soil.
Straight garden soil can be fine at a stretch and good for gardeners on a budget, but unless you’ve got nursery grade garden soil in your backyard, it’s probably going to cause you some troubles in the long run.
Sand/gravel mixes. Don’t just think about beach sand and road gravel here…We’re talking proper garden mixture sand and gravel blend with humus.
Just like the other options, sand and gravel can also be added to pots. In contrast to garden soil, a sand or gravel mix will have incredible drainage properties, and can give a more alkaline pH.
Plenty of plants like succulents, or sand dune species will absolutely love a sandy pot with some organic matter mixed through. It’s going to have the same structural properties as potting mix, but minus the nutrients and microorganisms, but can still be suitable for some plants.
Each of the options we’ve shown have their good and bad features. Rolling with potting mix only is probably the easiest and safest bet, if you’re not too worried about specifics. However, if you want to get experimenting, try playing around with ratios of sand: dirt: humus, and different mixtures of composts. You’ll learn pretty quickly which gives you the best results for the plants you want to grow.