This week marks the RHS's National Gardening Week, a campaign to encourage more people into gardening and horticulture. The theme of the week is 'Knowledge is Flower' a week long exploration of gardening myths.
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This year, National Gardening Week runs with the RHS Big Seed Sow, a community-growing campaign designed to get people sowing and sharing seeds, connecting with their communities and celebrating the start of a new growing year.
To mark the week, the RHS has shared five key gardening myths that many people believe are true. Which of these are new to you?
Digging for soil fertility
Many gardeners believe you need to dig to improve soil fertility. This is false, and digging actually releases soil nitrogen, which in fact can damage soil.
Here's more on no-dig gardening
Pot Planting
There has been a long-time misconception that growing plants in a pot is better, but pot planting also causes limited root spread and increases the need for watering and feeding. With some exceptions, it is better to plant in the ground.
Here's ideas for summer container planting
Crocks in pots improve drainage
Gardeners have long believed that crocks in pots improve drainage, but this is false. Disrupted capillary action and reduced soil volume mean they don’t help. Instead, crocks can be helpful for gardeners to prevent the compost from dropping through the hole at the bottom of the pot.
How to compost without the faff
Not watering in the sun
A long-held misconception is that watering in the sun scorches leaves. Though it is best to water at ground level, scorching does not happen. Scorching to new plants from lack of hardening off is far more common.
When to water plants in hot weather
Planting holes in clay soil
A common myth among those planting in clay soil is that it is best to make a large planting hole to fill with grit. However, this creates a sump, so the roots get waterlogged and rot, harming the plants.
How to grow a sustainable garden
Deeper soil isn't necessarily better
Many gardeners believe the deeper the soil, the better. Around 15cm is enough, 25cm at the very most. Those planting should use sharp sand rather than costly topsoil for deep beds.
Raised beds aren't necessarily best for growing vegetables
While raised beds can help in wet regions and clay soils, they can lead to over-draining, are expensive, and use environmentally significant resources elsewhere.
Vinegar isn't a good weedkiller
Contrary to popular opinion, vinegar is not a good weedkiller as it won't touch grasses and only harms broad-leaved seedlings, not larger plants.
Houseplants don't purify the air
According to our research, houseplants do not purify the air. Unlike ventilated homes with sparse plants, the original study was carried out in sealed growth chambers crammed with plants. There are plenty of other good reasons to grow houseplants, though.
Coffee grounds don't deter slugs
The evidence for coffee grounds' ability to repel ants and slugs is poor. The same applies to myths about eggshells, grit, pumice, and many other products.
Tomato leaves don't need to be removed
It has long been believed that bottom leaves should be removed from tomato plants. However, even lower leaves contribute to the plant until they go yellow (when they can be removed).
There is such a thing as over manuring
Although many believe there is no such thing as too much manure, organic matter, or compost, this is wrong. Overmanuring leads to excess heavy metals, phosphorus, and pollution.
Tree roots go as deep as the tree is tall
Tree roots form a shallow but broad 'plate' of roots and go wide instead of deep.
You don't need to fertilise every spring
It is believed you must add fertiliser every spring. However, most plants don't need feeding.
