PHEW it’s hot. Paul Richens, Gardens Manager at the Skip Garden in Kings Cross, shares some topical thoughts on how to get watering right.
WHAT IS IT about watering plants that people find so difficult? We often see two extremes: houseplants overwatered and drowned – troughs and outside pots not watered at all.
Is it because people don’t understand why plants need water? Let’s briefly look at how plants use water.
Actually, all living things need water because life requires a lot of chemical reactions to take place; for these to happen the chemicals must usually be dissolved in water.
Plants mix water together with carbon dioxide to make sugar. This takes energy, which plants get from sunlight; a process called photosynthesis. Water also helps plants stand up straight, even when they aren’t made of wood. They don’t have bones, but they do have cell walls and water pressure. A mature houseplant can transpire its body weight daily. This means it gives off a lot of water! If people needed that much water, an adult would drink 20 gallons of water a day.
Watering practice. We’ve always preferred that our skips and plant containers in the Skip Garden be watered using watering cans rather than hoses – it’s very hard to judge exactly how much water your hose has given, whereas you know exactly how much you’ve used with a watering can – but using a hose is quicker. So just take your time and really soak the soil.
The Skip gardening team joke that there are three recognisable stages of water stress:
1./ Dry soil – soil dry to touch, plants seem unchanged. Action: Water
2./ Flagging – leaves become soft and droopy. Action: Water
3./ Crispy – leaves and stems completely dry and shrivelled. Action: Compost
Rainwater is best. London tap water is okay, but is alkaline with a pH of 8 to 8.5. Rainwater has a pH of 6.5, which suits plants better; but don’t let that stop you using tap water if necessary.