Here you will find a few myths that are commonly found amongst gardening advice. Some have may have a spark of truth, but I hope to explain why they are generally wrong and why.
Newly Planted Trees Should be Staked
It depends. Spindly trees planted in a location that is susceptible to wind that could damage the tree, may need staked and guy-wired to prevent the tree breaking in severe conditions. However, staking a tree planted in more normal positions allows the tree to flex in the wind, and this encourages the development of stabilising roots and a strong trunk. Staking may mean that the tree takes longer to establish.
If staking is necessary, use soft flexible material such as fabric or bicycle tyre innertube around the tree, and remove the stakes and support after one growing season.
The Sun Shining on Water Droplets Burns Leaves
It is commonly said that you should avoid watering in strong sun in the middle of the day, because water droplets focus the sunlight and scorch the leaves. If that were the case plant leaves would get burned often when the sun comes out after rain. Plants have evolved to be able to have rain droplets on their leaves in sun.
What might happen, is that as water evaporates from the leaf surface, salts in the water are left behind, and if there is a high enough concentration in the water, the salt could scorch the leaves. But the reality is that that is unlikely.
Adding Sand to Clay Soil Makes It Easier to Work
Adding sand to clay soils may make the problem worse as you can create a hard mortar like soil. For sand to work it needs to be a large proportion of the soil. A much better option for improving clay soils is to add organic material.
See Soil Types
You Should Water Your Lawn Every Day in Summer
Like all plants, lawn grasses need water to stay healthy and green. In warm dry summer conditions, many lawns will quickly go brown if water is not applied to the lawn. To supplement natural rainfall many people will irrigate their lawn using an irrigation system, sprinklers, soaker hose or just a hose or watering can, and they will add a little each day.
It is much better for your lawn to water deeply and water infrequently. You might think ‘OK, if 35 mm of water (irrigation equivalent to 35 mm of rain) soaks down to the 35 cm depth required, I will apply 5 mm every day of the week.’ Unfortunately, this will not soak down to 35 cm because the first 5 mm will only soak down to 5 cm, and much of it will evaporate from the surface soil before the next 5 mm is applied. The next 5 mm may only add enough to soak a little further. Each time much of the water applied will evaporate off before the next application. The deeper the water the more slowly it will evaporate. Deep water will encourage grass roots to grow deep in search of the moisture, and this improves the lawn drought tolerance. So, apply 35 mm of water once a week.
Cutting the Lawn Short Means, You Don’t Have to Cut So Often
Do not mow your lawn too short. Higher mowing height favours deeper root growth. Mowing short causes roots to stop growing and may cause the death of deeper roots. Short mowing may also expose the soil surface to sun and wind, increasing evaporation and stress on grasses. It also induces grasses to grow more quickly so it does not save you time on mowing.
Fertiliser Helps Reduce Plant Stress
The myth is that plants under stress should be given fertiliser. This is only the case if the cause of the stress is lack of a nutrient you are providing in the fertiliser. If the cause of the plant stress is something else, then adding fertiliser may make things worse.
Identify the cause of the stress, compacted soil, waterlogged soil, disease, pests, salt spray, restricted roots, drought, etc. Then deal with that problem. Fertiliser can be applied if the symptoms appear to be a lack of nutrient and other stressors have been eliminated.
Water Plants Daily
Plants in hanging baskets and containers may need watering daily, but those in flowerbeds do not. It is better to water thoroughly and deeply a couple times a week; this encourages deep rooting and drought tolerance. Shallow watering encourages roots to stay up near the surface where they are more susceptible to drying out.
Cutting Earthworms in Half Results in Two Earthworms