Five gardening mistakes we see every week, and how to undo them

People bring us plants. Not often in a formal way, mostly a photograph on a phone at the counter, sometimes an actual pot in the boot with something brown and unhappy in it. After enough of those conversations you start to notice that the same five things come up again and again, and that almost none of them are about a lack of gardening talent.

They are ordinary, sensible sounding habits that happen to be wrong. Most of them come from caring too much rather than too little, which is why they are so hard to spot in your own garden. Here they are, roughly in order of how often we see them, along with what we would actually do about each one.

Watering on a schedule instead of on a finger test

Overwatering kills more potted plants than drought does, and the cruel part is that the symptoms look nearly identical. Drooping leaves, yellowing at the base, a general air of giving up. The instinct is to water more, which finishes the job. Roots need air as well as water, and a mix that never dries out is a mix where the air spaces stay full and the fine roots rot.

The fix costs nothing. Push a finger two or three centimetres into the mix before you water. Dry means water thoroughly, until it runs out of the bottom. Damp means walk away and check tomorrow. That one habit replaces every watering schedule you have ever been given, because a pot in February needs water far more often than the same pot in June. The RHS advice on watering plants wisely is a good grounding, and we went into the seasonal detail in our article on watering outdoor potted plants. Water in the early morning through a Highveld summer, and remember that an afternoon thunderstorm rarely soaks a pot properly, because the leaf canopy sheds most of the rain over the rim.

Garden soil in a pot

This is the one that surprises people most, because the logic seems sound. Plants grow in soil, there is soil in the garden, so soil goes in the pot. In the ground, that soil sits in a system with worms, roots, drainage layers and a water table underneath it. In a pot it is a sealed block, and after a few waterings it compacts into something with the density of a brick.

Most Gauteng gardens sit on clay that was scraped and compacted when the house was built, so what you dig up is worse than average to begin with. Use a proper potting mix instead. We use Bark Outdoor Potting Soil for outdoor pots, Indoor Potting Soil for anything inside, and Succulent Mix where sharp drainage matters. Work in some Bark Compost for anything staying put for a full season. Our article on whether garden soil can be used in pots goes through the physics of it, and the RHS explanation of soil types will tell you what you are working with in the ground.

The right plant in the wrong light

A shade plant in full Highveld sun bleaches and burns within a week. A sun lover in shade stretches, leans, goes leggy and never flowers. Neither problem is fixable with water or fertiliser, though both get treated that way, and we watch people feed and feed a plant that simply needs to be three metres to the left.

Spend ten minutes checking the actual light in the spot before you buy. Nine in the morning, noon, three in the afternoon, count the direct hours. Then match the plant to what you found rather than to what you hoped. Our free Plant Compare tool puts two plants side by side on light, water and size, and the Plant Library lists the requirements for each one. If you would rather skip the guesswork entirely, our pre planted sun range and pre planted shade range are already matched. There is also a longer read on finding the right plant for your spot.

Drainage that is blocked without anyone noticing

A pot with no drainage hole is an obvious problem, and most people avoid it. A pot with a perfectly good hole sitting flat on a paving slab is the same problem wearing a disguise, and almost nobody notices. Surface tension does the rest, water sits in the base, and the roots at the bottom drown while the top of the mix looks fine.

Lift the pot. That is the whole fix. A set of concrete pot feet raises the base a couple of centimetres, lets air move underneath, keeps the hole clear and stops the ring stain that a pot leaves on a patio. In deep pots, a layer of Pot Filler at the base keeps the bottom of the mix open and saves you a great deal of weight and soil. Indoors or on a wooden deck a drip tray is the right call, but outdoors in the summer rainy season a tray that never empties is just a puddle with a rim. The NC State Extension chapter on plants grown in containers explains why the water sits where it does. Our full range of trays, feet and extras covers both situations.

Feeding a plant that is already in trouble

When something looks poor, reaching for fertiliser feels like doing the caring thing. It is usually the opposite. A plant that is wilting, sunburnt, root bound or fighting off pests cannot take up and use extra nutrients, so the salts build up in the mix, draw water back out of the roots and add a chemical burn to whatever was already wrong. The tips go brown and crisp, and that gets read as underwatering, which starts the whole cycle again.

Diagnose before you feed. Find the actual cause, fix it, wait until you see new growth, and only then feed lightly. Through the growing season, little and often beats a heavy dose now and then, especially in pots where each watering flushes nutrients out of the drainage hole. Top dress with fresh compost at the start of each season and you will need far less fertiliser than you think. Our guide to fertilising plants has the detail, and the NC State Extension chapter on soils and plant nutrients is the reference we point people to when they want the science behind it.

What we would fix first

If all five of these apply to your garden, do not try to correct everything in one weekend. Start with the soil and the drainage, because those two are structural and everything else sits on top of them. Repot the worst offenders into a proper mix, lift every pot onto feet, and then leave the plants alone for a fortnight and simply watch them. You will be surprised how many recover without any further intervention.

The pot itself is worth a thought too, since a thin plastic pot in full Highveld sun cooks the root zone and a poorly made concrete one flakes after a couple of frosts. Ours are hand cast from our Fibre Concrete Mix, which is fibre reinforced and built for full sun, summer downpours and winter frost. When you are ready to redo the soil, our soils, compost and pebbles range has the mixes we use ourselves, and a bag of the right one will undo more damage than a season of good intentions.

Frequently asked questions

How do I know if I am overwatering my pot plants?

Push a finger two or three centimetres into the mix. If it is damp and the plant is still drooping or yellowing at the base, the problem is too much water rather than too little, and you should stop watering until the mix dries.

Can I use garden soil in pots?

No. Garden soil compacts into a dense block after a few waterings and suffocates roots, and most suburban Gauteng soil is compacted clay to begin with. Use a proper potting mix instead.

Why do my concrete pots need pot feet?

A pot standing flat on paving seals its own drainage hole, so water sits in the base and the lower roots drown. Feet raise the pot a couple of centimetres, keep the hole clear and prevent ring stains on the patio.

Should I fertilise a plant that looks sick?

Not until you know what is wrong. A stressed plant cannot use extra nutrients, and the salts build up in the mix and burn the roots. Fix the cause first, wait for new growth, then feed lightly.

What is the most common plant mistake in South African gardens?

Watering on a fixed schedule instead of checking the mix. It kills more potted plants than drought, because a pot in February needs water far more often than the same pot in June.