Garden Guru: Gone to pot

By Neil Ross

Flowering container plants need consistent care to maintain their looks. Photo / Supplied
Flowering container plants need consistent care to maintain their looks. Photo / Supplied

When Jack arrived on the scene, I thought he was going to be a lot of work - what with feeding and watering and arranging for someone to care for him during the holidays - but Jack's needs pale into insignificance compared to the pots on my patio.

Guinea pigs can be hard work - especially if they are your first proper pet - but if you thought that animals can tie you down, try planting a tub of petunias. I made the mistake of giving in to my wife's partiality for summer colour and splashed out on some potted colour to bed out in a range of barrels and pots.

Containers are fantastic vehicles if you have something you want to show off, but as accommodation for living things they are the floral equivalent of a cell in Guantanamo.

Containers dry out quicker than garden beds and, because we usually skimp on their proportions, the occupants have precious little soil from which to feed in the first place.

The result is that nothing less than intensive care will keep the prisoners co-operating - especially bedding plants which need lots of feeding and water.

Watering through a hot summer can easily turn from pleasure to pain, but there are several shortcuts to be made to avoid your pots becoming more trouble than a parched hamster.

My first lesson for next year will be to go easier on the potted colour and opt instead for more permanent plantings which tend to have deeper root systems.

Many plants have iron constitutions and it's good to have plenty of these, but a bit of floral exuberance always adds a decadent touch - just put it in as large a container as you can and keep it close to a tap.

Getting the compost right is crucial. A common problem with most potting composts today is that they contain little true soil but are made of light, spongy organic matter such as peat or composted garden waste. Organic matter is great for holding moisture like a sponge, but when it dries out - just like a sponge - it becomes resistant to re-wetting and, although we may think we have soaked our plants back to life, most of our emergency water simply disappears between the shrunken compost and the pot sides.

There are now specially designed wetting agents on the market; granules which you can incorporate into existing compost to help it absorb water better, but so long as you are willing to soak a dried-out rootball - pot and all, for several hours in a bucket of water - you will eventually rehydrate the roots.

Soil-based composts like the "John Innes" range not only hold on to moisture better, but do the same with nutrients. They are heavier and cost more but don't shrink or rot away over time as organic composts tend to do.

You can perform a simple trick to see if a container filled with organic compost is drying out: rap it with a rock or a knuckle and, if it rings rather than resounds with a dull thud, the compost inside has shrunk away from the pot wall and needs attention.

It's better to flood containers once a week than to piddle about with watering cans every two days. I soak my pots until water flows out of the bottom, but I don't leave it at that. After soaking everything, I repeat the circuit a second, sometimes third time. The first dose only starts to rehydrate the compost.

Gardeners are divided about the benefits of water-holding crystals. Personally I can't trust a product that is bright blue to begin with and transforms into something resembling a dead jellyfish. All that gelatinous goo sitting around the plant roots must mean less room for nutritious soil.

No, my most helpful watering aids are simple pebbles and saucers. The pebbles are used as a mulch in the top of the pot. They look clean, shade the compost surface and allow you to flood the top of the pot with a hose without sloshing soil over the deck.

Saucers under pots to catch excess water and allow compost to reabsorb it back up into the pot are a must. The cost may be off-putting, but you can use anything - a dustbin lid, tea-tray or baking tin. They may not look pretty, but they will cut the hours spent standing around at the end of the hose so you can get back to the important stuff - like retrieving a frightened rodent from behind the sofa for the third time in one day.

Watering tips

* Group pots so they are easier to water - gather less thirsty plants so you only have to water them every other time you do the rest.

* If you haven't already, look at the accessibility of outside taps and try to add rain-collecting water-butts to gutters to make watering easier.

* Two large watering cans are easier to use, as one can be filling while you empty the other. Cans also keep you fitter and more water-conscious.

* When re-potting, make sure you leave compost 5cm below the rim of the container to allow for mulch and for a good watering to form a puddle on top.

* Use a few large containers rather than lots of fiddly small ones which dry out quickly. And try to choose non-porous materials.

* Many plants in containers will put up with a few months placed in a shady corner of the garden in summer, which will reduce their thirst.

- Herald on Sunday

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