Green manure crops

Green manure crops are used in winter to replenish soil ready for planting in spring, keep weeds down and protect fallow beds from erosion.

Gerard Martin, co-owner of Kings Seeds with wife Barbara, says gardeners should grow green manure every year and rotate crops every two years.

“This breaks the cycle of goodness being sucked out of the soil and the build-up of pests and diseases,” he says. “Green manure is a natural way of putting goodness back in. [Read more by Gerard on the topic here.]

“At this time of the year you need a cool-germinating seed and I like to mix different species – such as peas, oats and lupin – together. The mix is a good nitrogen fixer and breaks down quickly.”

The pea-oat-lupin green manure mix from Kings Seeds. Photo: Kings Seeds

Crops should be cut (a lawnmower set on high can be used) and hoed in before they flower, or the bed can be turned over by spade. “I like to dig it in,” Gerard says, “because you incorporate a bigger biomass.”

Phacelia tanacetifolia is a vigorous grower that breaks down quickly when dug in and has the advantage of being unrelated to any other vegetable. If left to flower it will attract honeybees, hover flies and other beneficial insects.

“If you’re not planting until early to midsummer you can grow two manure crops and I would recommend the mix and phacelia.”

Phacelia tanacetifolia. Photo: AnemoneProjectors (Wikimedia)

Broad beans grown in winter can be used as green manure once they’ve cropped, while frost-tender soyabeans and buckwheat are good manure crops for summer.

Mustard will take about 30 to 45 days from sowing to cutting, while the pea-oat-lupin mix will take 50 to 60 days. Although he knows a lot of people use mustard, Gerard prefers to give his ground a rest from the brassica family (read about club root here).

“Growing a green manure crop is much better than, say, fumigating the soil with a spray when you’re killing the bad insects, bacteria and fungi, yes, but the good ones too – and 95% of the bacteria and fungi in soil are good.”

Read more on the topic here and here (both English websites).

Gerard and Barbara have owned Kings Seeds, which opened in 1978, for 15 years and operate from the countryside south of Katikati.

Barbara and Gerard Martin. The warehouse at 189 Wharawhara Rd (museum is on the corner) is open to the public every Friday until noon. Photo: Sandra Simpson

Each year Kings Seeds sells (to commercial growers and home gardeners):

  • 5 tonnes of peas for shoots
  • 5 tonnes of purple radish seed for spouting
  • 3 tonnes alfalfa seed
  • 2 tonnes of wheatgrass for sprouting
  • 1-2 tonnes bull’s blood beetroot seed
  • 1 tonne coriander seed.

“A home gardener will buy 500g of seed at a time,” Gerard says. “A commercial grower will take 300kg every second month.”

There are 10,000 seeds per gram for watercress, while a single broad bean seed weighs 2-3g.

Some of this article was first published in the Bay of Plenty Times and appears here with permission.

Suddenly, autumn

It seems like the trees have changed colour almost overnight – the middle of the day is  still surprisingly warm but evenings and mornings are definitely colder. One of the best places to see autumn colour in the Tauranga area is McLaren Falls Park.


A planting of liquidambers set off by the evergreens that surround them. Photo: Sandra Simpson

“We’re going to have to stop calling it a hidden jewel,” says park ranger Gary Borman. “People have woken up to how neat it is out here.”

Tree planting in the 190ha park began in 1965  and members of the Bay of Plenty Tree Society still gather there every Monday afternoon to work. The arboretum features some rare and unusual trees and Gary is trying to bring more colour into the park.


The colours of Acer rufinerve, the snake-bark maple. Photo: Sandra Simpson

“I want people to see a good dose of colour in autumn when they get to the vista at the top of the lake. The volunteers will continue with rare and unusual trees and I will aim plantings at flowers and foliage.”

The park is home to what is believed to be the only tree of its kind in New Zealand – an Emmenopterys henryi, native to southern China. “It doesn’t look much,” Gary says, “but it’s very special.”

The swamp cypress (Taxodium distichum) planted beside and in the lake are one of the few deciduous conifers, the needles turning rust-orange before falling, and the park is also home to several dawn redwoods, another deciduous conifer.

Department of Corrections workers also work at the park and over the past couple of years have been linking existing tracks so visitors can walk from Cherry Bay along the lakeside to Top Flat up to the lookout at Pine Tree Knoll back down on a new track to the Ponga Grove and Nikau tracks, across to the Waterfall track and back to Cherry Bay without having to double back.


The sorrel (Oxydendrum arboreum), native to the eastern United States, holds its white flowers even while the leaves are changing. Photo: Sandra Simpson

Although it’s hard to pick a peak moment for autumn colour – some trees turn and shed earlier than others and weather plays a part too – Gary reckons the weekends in the middle of May are some of the prime days to enjoy the show.


If you go to McLaren Falls Park on Mother’s Day look out for environmental art, something of a tradition by two local families. Photo: Sandra Simpson

Charged over a dead plant

In my April 30 post I referred to a news brief that said Clive Higgie of Paloma Gardens had been charged by the Ministry of Primary Industries – not over a Pacific kauri that was the reason for the raid on his property, but another plant.

Today, the Wanganui Chronicle reports that Clive and wife Nicki, a former district councillor, have indeed been charged – over a dead Ficus watkinsiana (strangler fig)! Read the full story here.

This list of “organisms” present in New Zealand causes plants people headaches on a daily basis. You’d think the MPI would do something about updating it – spend the money on that rather than raiding the Auckland Regional Botanic Gardens! I couldn’t easily find a copy of the list on the page of the MPI website that apparently contains all its lists and registers.

Beware Legionnaire’s disease

Legionnaire’s disease can and does happen to home gardeners – it is at best a nasty illness, at worst a fatal one. What causes it and how can we be on guard against it? There are at least 50 different types of the Legionella bacteria, only one of which is found in water systems, while another is linked to inhalation of particles from potting mix and garden soil. Read NGIA advice and information here.

There is now a national Legionella Working Group, prompted in part by a Fair Go item about warnings and information (or lack of)  about the disease in garden centres.


20 years and growing!

 The Bayfair Community Garden is celebrating its 20th birthday on May 31 with a dinner for all past and present volunteers and sponsors at the Mt Maunganui Club. For details phone the Hillier Centre, 07 575 9709, or Jo Stock, 021 647 676.

The Bayfair Community Garden was the first of my six years of weekly articles for the Bay of Plenty Times, so it was fitting that it was also one of my last …

Jo Stock at the Bayfair Community Garden. Photo: Sandra Simpson

In the 12 months to February volunteers at the Bayfair Community Garden have donated 393 boxes of fresh vegetables to Tauranga’s Foodbank, continuing a tradition that started 20 years ago.

Up to 16 volunteers turn out in summer and about 10 in winter twice-weekly – Tuesdays are picking and packing banana boxes of produce and Fridays are work days.

Volunteers are all ages, although mostly retired, and include American Beth Cocchiarella who spends half her year in Mount Maunganui and half her year in Washington State, and a couple of young women who bring their children along. Smoko (morning tea) is a good chance for a chat and laugh, although laughter never seems to be far away, even when the garden’s at its busiest.

Donnas Mitchell (left) and Beth Cocchiarella get to work digging a new bed. Photo: Sandra Simpson

The garden project is co-ordinated by Jo Stock, a retired secondary school teacher, who joined the volunteers 18 years ago and oversaw the garden’s move from a site needed for development to its present location in 2000.

“This was a paddock on February 2 and by March 31 we had the last bed planted,” Jo says. “The soil looks good today but it’s sitting on a bed of a sand – and that’s what we started with.”

Jo, who plants by the moon because “it causes less trouble”, grows seedlings at home so the garden is always productive and is careful to choose veges that food parcel recipients know. (See a New Zealand moon calendar here.)

“New Zealanders aren’t very good at so-called gourmet veges,” she says. “I’ve only had half-a-dozen aubergine plants in this year because people don’t know what to do with them and aren’t willing to try.”

The former teacher of food and nutrition has tried including recipes with certain veges but has been and sat at the Foodbank and watched people choose their vegetables. “They like the bog standard stuff, even bok choy is too hard for many of them and all you have to do is steam it.”

Barney Quaddel of Maungatapu in Tauranga weeds the red onions. Photo: Sandra Simpson

Unsterilised sheep manure is believed to have been the source of club root, a fungal disease that destroys brassica crops, which has infected half the garden for nine years (the sheep had been grazing an infected crop).

“Five weeks after the manure went on, we had it,” Jo says. “We’ve tried every darn thing  – if anyone tells you they know how to get rid of it, they don’t. It’s terrible stuff.”

Something that has been helpful when planting is to mix half a teaspoon of potassium permanganate and 2 dessertspoons of salt in 9 litres of water. “We put 3 cups of that in each hole when we’re planting and it seems to help protect the seedlings,” Jo says. Read some organic control suggestions here.

People passing between the two sides of the garden use a foot bath and tools are sterilised to prevent its spread (so far, successfully). Jo has “given in” in the affected end and started using raised beds to isolate crops from the ground – each bed is lined with polyurethane and has a gravel base to assist drainage.

The garden has a five-bin compost system, a worm farm and its own water bore, although needs to find cash for repairs after problems this summer, suspected to be both the pump at the top and the bore needing to go deeper.

“We grow everything here for $1000 a year,” Jo says. “It’s nothing, but we have no cash so I’m always scrabbling round trying to raise a bit.”

Her father was a World War 1 veteran living in Colville on the Coromandel Peninsula  –  his wounds won him a war pension but not much else.

“There were six children and we were always very poor,” Jo says, “but we never went hungry because we always had vegetables from his garden.”

Keri Seuseu of Mount Maunganui and Sally Quaddel of Maungatapu enjoy a cup of tea. Photo: Sandra Simpson

This article was first published in the Bay of Plenty Times and appears here with permission. It has been updated.