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Summer is here! The trick to getting abundant berry crops and other organic garden tips

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Summer is such a waiting and watching period. All the hard work of spring is about to come to fruition – if we protect and nurture our precious plants and their ground crew. Diana Noonan shares her experience of growing food organically and reminds us, as we tinker in the garden, to enjoy the riot of colour all around and to marvel at how the earth, the essence of life, really can bring forth food in abundance.

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Get ready for spring: seasonal gardening tips and tasks

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Tips and tasks for the July/August māra,
by Diana Noonan

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Tohea! Ko te tohe i te kai –
Be strenuous – it is a struggle for food.

While the the days are short and nights are cold, there’s still so much we can do to make sure our gardens are in the best possible state to enter the growing season. From clearing out pest insects and adding nutrition to the soil, to encouraging the earliest food-bearers, and even sowing some super-hardy vegetables, winter is a much more active gardening season than you might imagine!

Bring in the birds

Birds are one of our greatest assets in the organic garden, especially in winter. They come into my garden in flocks and return again and again to devour overwintering pest insects such as spider mites, aphids, mealy bugs, caterpillars, and scale insects.

Silvereyes appear to be especially deadly hunters, gobbling insects all day. To take advantage of their appetites, I make sure that all nets are removed from berry bushes and fruit trees and sections of the garden that don’t require protection from rabbits and possums.

If conditions are dry enough in the garden, use a rake to disturb mulches. This exposes pests such as grassgrub, slugs, snails, and their eggs, and allows other birds, such as thrush and blackbirds, to discover them. I scratch around the base of my fruit and nut trees with a rake to achieve the same results. Providing bird baths and feeding tables will encourage even more birds into your garden.

Dig in!

Towards the end of winter, if the ground is dry enough, I take the opportunity to dig my green manure crops (also known as cover crops) into the soil. In my garden, these are lupin, vetch, grain, or tick beans, the seeds of which I sowed en masse in autumn.

These plants take 6-8 weeks to break down in the soil, so digging them in now means they will be ready to provide nutrients to spring-sown plants. I dig my green manure crops to a depth of just 10-15cm (I want to disturb the soil as little as possible), turn them over, and lightly chop them back into the ground. If the weather is horribly wet, I’ll cover the bed with black plastic to protect the soil while the goodies decompose.

Sow early!

In winter, it’s not so much what early seed we sow, but how we sow and protect it, that’s important. Birds are more desperate for food in winter than in any other season, so netting or covering what you sow is essential. I always cover small seed (such as spinach and mesclun mixes) with clear plastic, raising it a few centimetres off the ground with the help of narrow boards.

This keeps the plastic just high enough to trap the heat beneath, hurry along germination, and let the seedlings develop their first true leaves. After that, it’s on with the bird netting.

To combat the winter wet, I sow smaller seed into slightly raised rows to assist with drainage and cover them, to the recommended depth, with light, dry, soil or friable compost.

In warmer months I always soak larger, more robust seed, such as pea and broad bean, before sowing to hurry along germination, but I never do this in winter. In winter, soaking the seed often causes it to decay in the already-damp ground before it has time to sprout. And even though the seed is larger, it is also netted.

Sow me now 

Flowers
In warm and mild regions (undercover or outdoors in seed trays or individual pots, depending on location): foxglove, hollyhock, bachelor’s button, cosmos, evening primrose, echinacea, marigold, nasturtium, statice, sunflower, sweet pea.
In cold regions: As for warm and mild regions but sow into seed trays and place on heated propagation mats.

Herbs
In warm and mild regions (undercover or outdoors in seed trays or individual pots, depending on location): basil, chervil, dill, fennel, marjoram, mint, parsley, thyme.
In cold regions: As for warm and mild regions but sow into seed trays and place on heated propagation mats.

Veges
In warm and mild regions (outdoors): Asian greens, broad and dwarf beans, beetroot, broccoli, cabbage, carrot, cauliflower, green manure crops, lettuce, parsnip, onions, potato, radish, rocket, silverbeet, spinach, spring onion.
(Undercover in seed trays or individual pots): aubergine, celeriac, capsicum, cucumber, celery, leek, melon, pumpkin, tomato.
In cold regions (undercover or outdoors, depending on location): brassica, broad beans, cool season microgreens, lettuce, peas, pea shoots, perpetual spinach beet, silverbeet.
(Undercover, in seed trays or individual pots): chili, capsicum, sweet corn, tomato

Healthy herbs

Some of the very first ‘greens’ to come through the soil toward the end of winter are hardy, tasty herbs. Chives, marjoram, fennel, and sorrel are longed-for flavour boosters in my late winter garden and I lavish attention on them. I make sure to mark their whereabouts in autumn (as some all but disappear beneath the ground as the days shorten), and toward the end of winter I clear the sites of fallen leaves and other debris.

I carefully scratch away any weeds, and mulch around (but not over) the spots. I pop a cloche (a cut off plastic soda bottle) over the delicate foliage as it emerges to lock in the heat and protect it from browsing animals.

I harvest cautiously at first, to keep the growth coming, and more vigorously after 2-3 weeks, as these ‘earlies’ are often the first edibles to run to seed.

Gear-up the greenhouse

If you’re lucky enough to have a greenhouse, this is the time to press it into service (if you don’t have a greenhouse, you can build a simple cloche from hoops of willow pushed into the ground and covered with clear plastic held down with a brick at each end). Whatever you do, don’t wait until the start of spring to raise your seedlings. It can take from 3-8 weeks, depending on what kind of seed you sow, before a seedling is ready to transplant. Wash down the greenhouse inside and out to let in more light, and remove any overwintering plants that may be hosting pest bugs (be sure the bugs don’t drop off inside the greenhouse as you shift them).

Set up staged shelving to hold your seed trays (staged shelving is similar to a set of steps, and allows all seedling equal access to the light). Cover seed-raising containers with a sheet of glass to stop mice scratching them up in search of food, and once the seeds have germinated, check nightly for signs of slugs and snails.

Don’t forget to keep the greenhouse door shut to keep out the birds.

Bare necessities

It’s fruit and berry planting time, and the best deal is to purchase those that are bare-rooted.

Bare-rooted plants are dug straight from the soil while still dormant. Their roots are wrapped in a covering to stop them drying out. Bare-rooted trees and bushes have a better start in your garden than potted plants, the roots of which are likely to have been restricted for many months. Niche nurseries often specialise in bare-rooted plants so you usually have a great choice of variety.

Transplant me now 

Flowers
In warm and mild regions: alyssum, Canterbury bells, dianthus, delphinium, gypsophilla, larkspur, marigold, sweet William, sweet pea, viola.
In cold regions (where conditions permit): alyssum, gypsophilla, larkspur, marigold, sweet pea, sweet William.

Herbs
In warm and mild regions: mint, parsley, rosemary, sage, thyme.
(Under cover or when danger of frost has passed): basil and lemon grass.
In cold regions: chives, parsley, rosemary, sage, thyme.
(Under cover): marjoram.

Veges
In warm and mild regions: asparagus crowns, broccoli, cabbage, cauliflower, lettuce, onions, silverbeet, shallots, strawberry.
In cold regions (undercover, in planter bags that can be moved outdoors when space is required): brassica, celery, hardy lettuce, perpetual beet, rocket, silverbeet, spinach.

Diana Noonan lives in the Catlins where she grows 70 percent of her food using a variety of methods including permaculture food forest to French intensive. 

Broad bean new growth showing leaf curl and shrivelling.

Keep your garden safe from killer compost

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When Minette Tonoli’s lifelong dream finally came true, moving into a beautiful homestead in May 2019, she was convinced it was going to be the ‘year of abundance’, harvest baskets overflowing with organic produce, and the pantry filled with preserved bounty.

Instead it became the year this herb lady turned into ‘herbicide lady’. 

This article was first published in Organic NZ, March/April 2020.

Broad bean new growth showing leaf curl and shrivelling.

Broad bean new growth showing leaf curl and shrivelling.

Stunted, twisted vege plants

Transplanted broad beans in my newly established potager garden soon started growing bizarrely with new leaves that were hardened, curled and twisted. Snow peas had similar misshapen leaves, as did hundreds of heirloom tomato seedlings that grew stunted, with older leaves cupping, and new leaves forming shepherd’s crook or fiddleneck distortions. 

While there are many reasons for leaf curl, including physiological damage due to watering problems (too much, too little, or inconsistent), fluctuating temperatures, insect infestation and viral infection, none of these seemed to be the right answer across the board for all the plants affected. 

Diagnosing the problem

Soil tests are expensive for home gardeners, so I compared my plants to online pictures of herbicide-damaged growth and they correlated exactly – I had found the most likely culprit: pyridine carboxylic acid herbicides. I knew these types of herbicides weren’t used on my property, and because of the pattern of plants affected, could not blame spray-drift.  

Various savvy friends and experts in the organic gardening world agreed that the most likely source of contamination was the vegetable soil mix I had brought in from a landscape supply yard. 

My garden had fallen victim to ‘killer compost’. Killer compost is a term given to compost, soil and manure mixes that contain high enough levels of persistent pyridine herbicides to negatively affect non-target plants such as homegrown vegetables.  

Certified organic soil and compost mixes should be free of these residues, but only if they are pure. The vege mix I bought was made up of certified organic compost and added manure, and I think it was the manure that contained residues.  

Distorted tomato leaves showing leaf curl and shrivelling.

Distorted tomato leaves showing leaf curl and shrivelling.

How do these herbicides sneak in?

Pyridine herbicides are used to deal to a range of broadleaf weeds in pastures, grain crops, sports grounds and commercial turf, recreational parks, native forests, some fruit crops, and for roadside maintenance.  

The Environmental Protection Authority of New Zealand (Te Mana Rauhī Taiao) regulates the registration of products containing these herbicides, and there are labelling laws and restrictions on the sale and use of products containing these chemicals. Most are banned for home use (since 2008), and require commercial operators to have safe handling certification.  

With seemingly all the required legislation in place, it could only be through end-user ignorance of how these chemicals work and degrade that herbicide-contaminated hay, grass, manure etc. end up in commercially available home garden soil mixes. Horse manure and hay sold on the roadside are not regulated, and may contain these herbicides. 

Generally, pyridine herbicides are brought into the home garden via one of the following three pathways:  

  1. Contaminated mulch such as hay, straw, and grass clippings from crops on which the herbicide was used. 
  2. Contaminated manure and soiled bedding from livestock such as cows, sheep, pigs and horses, that have eaten crops treated with the herbicide. 
  3. Contaminated composts that were made using above inputs. 

Once the herbicide is taken up by susceptible plants, it moves systemically to growing tissues, deregulating metabolic pathways, causing uneven cell division and growth. Plants affected do not produce well, if at all, and may die.  

Many of these herbicides are very persistent in the environment, are stable in water, don’t degrade in anaerobic environments, and are highly mobile – one study found picloram residues in an untreated site a kilometre away from the original application site, up to two years later. How to heal contaminated soil

The herbicides degrade in soil over time, and active cultivation and soil amendments may speed up this degradation.  

  • Get the soil microbiology teeming as a first priority. The most effective pathway of degradation of persistent herbicides is its decomposition by microbes.  
  • Cultivate the soil often to expose all parts to soil life, water, and sunlight (UV). 
  • Using activated carbon to bind to the herbicide in the soil has also been put forward as a solution. 
  • Mycoremediation, using beneficial fungi, is another option. Although little research exists, this is one of the methods I am trialling. 

Don’t compost affected plants

Thai pink egg showing stunted and shrivelled growth.

Thai pink egg showing stunted and shrivelled growth.

Don’t compost anything that comes from your affected garden, including manure from animals you fed from it. The herbicide chemicals bind strongly to plant material and neither plant and animal metabolising, or home composting, will degrade it sufficiently. Best bet is to bin it – in council refuse, NOT green waste.Page Break 

My affected tomatoes, which were transplanted into clean soil, have recovered somewhat and are flowering and setting fruit, although they are not nearly as large or productive as normal. Tomato plants I left in tainted soil have not recovered, growing spindly and stunted, with only a handful setting fruit which are deformed and tasteless. Can you eat the produce?

There seems to be a consensus that produce grown in soils containing low levels of these herbicides are fine for human consumption, although some reports also indicate possible health concerns, following observations in laboratory animals fed with moderate to high doses.  

By seeing this experience as a learning opportunity, and educating others about killer compost, I still managed to turn it into a season of abundance – I may not have the fresh produce, but my cup of knowledge overflows. 

Plants most likely to be affected 

  • Solanaceae, e.g. tomato, potato, chillies, etc. 
  • Fabaceae, e.g. beans, broad beans, peas, etc. 
  • Asteraceae, e.g. artichoke, dahlia, Jerusalem artichoke, lettuce, etc.  
  • Vitaceae – grapes 
  • Rosaceae, e.g. roses, loganberry, raspberry, etc.  
  • Umbelliferae, e.g. carrots, celery, parsley, etc. 

 Least susceptible plants 

  • Grass crops and plants in the brassica family are unaffected and can be grown in contaminated soil. 
  • Pumpkin and squashes are only slightly susceptible, and still produce well. 

Chemical culprits

These are the three pyradine herbicides most commonly used in NZ. For highly susceptible plants, such as tomatoes, toxic levels of these herbicides are 1–3 parts per billion – equivalent to about half a teaspoon of herbicide product in an Olympic-sized swimming pool. 

Chemical name 

(sold under various brand names) 

 Level at which residues are toxic to non-target plants (parts per billion)  Half-life in soil (days) 
Aminopyralid  1–3 ppb   32–533  
Clopyralid  1–3 ppb  60–425  
Picloram  10 ppb  30–400  

 About the author

Minette Tonoli in her garden.

Minette Tonoli is an Earth Mother who is passionate about herbs, and loves to inspire and encourage others toward soulful gardening and the use of homegrown plants for food and healing. For more images of pyridine-affected plants, see her website: meadowsweet.co.nz – direct link to the photo gallery: bit.ly/2Rm97NA  

References

  1. The United States Composting Council. 2015. Understanding Persistent Herbicides. www.compostingcouncil.org/resource/resmgr/images/USCC-PH-Fact-Sheet-1-for-web.pdf.  
  2. The United Kingdom Waste and Resource Action Program. 2010. An Investigation of clopyralid and aminopyralid in commercial composting systems: www.wrap.org.uk/sites/files/wrap/Clopyralid%20Report.pdf 
  3. Beyond Pesticides factsheets on: 

 Further reading 

 

organic asparagus

Organic Asparagus: Yield way above conventional

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Organic NZ Magazine: May/June 2005
Author: Annie Wilson

On the much lauded Heritage Farms, just out of Cambridge, manager Richard Prew has had a surprisingly large and successful crop of asparagus. It was enough to draw commercial grower Annie Wilson to check things out.

The Waikato is the main asparagus growing area in the North Island, chiefly because it has areas of flat, fertile, well drained sandy loam – soil suited to the needs of asparagus, which is a long-lived perennial and likes good fertilisation.

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