How to adapt your vegetable garden to El Niño and the coming heat

Kerikeri growers Irwin Lawson and Geraldine Davy may have answers for home gardeners struggling to keep their gardens going strong in the summer heat.

The couple transformed a bare paddock in Northland into a lush tropical garden that is a paradise for birds and biodiversity thanks to clever plantsmanship, shelterbelts and irrigation.

But it is in their vegetable garden and orchard where home gardeners will learn lessons about dealing with an expected warm, dry summer, the projected El Niño weather pattern and climate change.

They first began by creating an upper story canopy of tropical plants to provide shade and shelter, alongside an established border of redwoods and acmena. Using plants from a more tropical climate is something we all have to start thinking about.

They also took time to observe and interact with their environment (such as following the track of the sun) and existing irrigation system to find the best location for their vegetable garden and orchard.

“We’re on an older property and like a lot of the older properties in Kerikeri were on irrigation schemes, so we’re pretty lucky to be on one of those still left. So we have extra water plus our tank water that we use for drinking and so forth,” says Irwin.

“And we mulch – to help keep moisture in the ground – quite frequently anyway, because we’ve got big lawns and I have a catcher on my mower, so it collects the grass pretty well.

“That’s the easiest mulch to collect and most effective. Straw and hay are too expensive for us. I always try to use what’s available. I have a small mulcher as well, so we can mulch branches and things.”

Geraldine says they complement their natural shelters with windbreak cloth over the garden.

“You get a bit of a dip in the sunshine over the day, but it gives quite a bit of protection from the heat and also birds,” she says.”

They are also practising planting outside traditional growing times for vegetable plants – for example, transplanting things like tomato plants well before the traditional time of Labour weekend.

Being in the warm, dry north, the couple are used to their greens bolting and going to seed, says Irwin.

“The only solution is to harvest them quicker or come up with some inventive recipes. For instance, I’ve got a recipe where I found a bit of broccoli going to seed, so I chop it onto a bit of baking paper on a tray and grate some cheese over the top and add a little bit of onion and salt and pepper. It makes quite a bit of food.”

Geraldine says they will cut plants like broccoli when it’s going to seed. “It manages to come back again. The heads are smaller but at least you haven’t killed it off.”

They’re also practised at succession planting, so will have lettuce, broccoli and other salad greens constantly on the go.

The couple have problems with kikuyu weed, which loves the heat, and have almost given up trying to control it.

“We once sprayed the kikuyu around the fruit trees, but it killed one of the trees. The spray hadn’t gone near the leaves but soaked into the ground onto the tree’s roots.”

The couple try not to resort to sprays now, instead using a weedeater to keep the kikuyu off fruit trees, paths and garden borders. “I just stick a spade up against the tree, so I don’t damage it,” says Irwin.

Thai herb garden

It’s easy to find parsley, basil, thyme and rosemary, but why not try growing other herbs to make your international dishes taste truly authentic?

Thai cuisine relies on balancing the different elements of taste – sweet, salty, sour, bitter and spicy. Different ingredients fit into these categories: chillies for spice, say, or lemongrass and kaffir lime leaves for sour.

Chillies and the various basil (such as holy basil and Thai basil) like a warm, sunny spot, so grow these plants together in one container.

In summer, coriander needs shade, and since you’ll most likely be harvesting the roots – which are a quintessential ingredient in Thai food – give it its own container. You can harvest both the leaves and the roots. The roots are harvested 30-50 days after the seeds germinate, when the largest above-ground stem is about 5mm in diameter. Pull out the whole plant when gathering the roots.

Ginger and its relative galangal can be grown in a greenhouse or a warm room, and also outdoors. They grow from root sections, technically rhizomes. Give these plants their own container, at least 30cm deep. Slice the rhizome (available from organic grocers – choose a plump one free of wrinkles) into pieces, making sure there’s at least one bud on each piece. Plant in free-draining mix that’s had compost incorporated. Each piece of rhizome needs about 20cm of space. Plant the rhizome facing upward and position the container in partial shade. Keep the soil damp but not soggy.

Turmeric has a bitter flavour and can also be grown from rhizomes, and given its own container too.

Lemongrass and makrut lime have a bouquet of complex flavours, and are also best in separate pots. Both like a warm, sunny spot away from frost, so grow in containers so you can move them into shelter over winter.

Put out water for birds

Not only does your garden suffer from arid conditions, so to do birds. Provide them with a water-filled birdbath or some thoughtfully placed vessel in which they can safely dip out of view of predators such as cats. The sight of birds happily bathing, flicking water here and there, drinking and generally revelling in the cool water is a heartening one, and you can be sure the birds will be enjoying the experience as much as you. Change the water as often as you can – no one likes to drink their bathwater – and fill whatever container you’ve provided with rainwater if you can.

Gardening by the moon

December 1: Turn the compost heap. December 2-3: Sow root crops. Keep beds moist until seeds germinate. December 4-8: Harvest everything that is ready. Fertilise and cultivate the soil.

Gardening by the maramataka

Here the summer wife Hineraumati commands Rehua (the star Antares) and he becomes apparent through the midsummer haze and mist which itself pre-empts the drying up of soil and vegetation. This is the crucial period for understanding plant needs to survive drought and persistent drying winds such as the Canterbury nor-easters. Moving towards the end of the month, early red berries such as porokaiwhiti (pidgeonwood) or taupata (Cosprosma) are ready, and birds will find them for food. The red and black currants in the garden will also be ready at the same time. Whiro (new moon) is due on the night of the 12th and Te Rākaunui (full moon) on the night of the 26th. Accordingly, the period following Whiro (13th to 15th) and the period following Christmas from midday on the 26th to the 28th are suited to garden activities of all sorts. Perhaps ensure the last of your new plants are planted during this period. You can now put your feet up for the upcoming start to 2024. Dr Nick Roskruge

Source: stuff.co.nz