Category Archives: Soil health

Dealing with black spot fungus in pawpaw / papaya

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Last year we reluctantly pulled out the last of our pawpaw trees.  This was because we were not able to keep the black spot fungus under control sufficiently to be able to harvest fruit of a quality we were prepared to eat.  It was a very difficult decision because there is nothing more delicious than a tree-ripened pawpaw.

This tree and another which we dug out few years back were planted ten years ago and probably gave us about a tonne of fruit over that time.

The black spot fungus didn’t show up in the first 2-3 years, and during that time it was not unusual to have more than 20 fruit on each tree at one time, and to harvest a fruit every couple of days at the height of the season.

However, once the fungus became established for many years we were harvesting smaller than normal fruit which did not have the full “ripe pawpaw” flavour and was infected with white spots which we cut around.

We tried a range of approaches to controlling the fungus, including spraying with wettable sulphur and Seasol.  Unfortunately without any clear guidance as to how often to spray, and without any certainty that these were the correct measures to take, combined with long periods away from home, we didn’t persist with any particular regime.

However we did get the impression that both the sulphur and the Seasol had some beneficial effect, but only in the presence of good soil health and regular fertilizing.

Today I came across a post on Jerry Coleby-Williams’ website on how to fortify your pawpaw plants to better withstand the effects of this exotic fungal disease caused by the fungus Asperisporium caricae.

What he recommends is a combination of:

  • spraying with wettable sulphur  monthly from (February to October);
  • regularly removing severely infected leaves and fruit and all fallen foliage (all year round);
  • removing old mulch at the end of autumn and replacing it with fresh; and
  • maintaining the overall health of your pawpaw by a combination of good drainage and modest but regular feeding.

Jerry emphasises that well nourished pawpaws are more important for disease control than spraying. Go to his website to see what he prescribes in detail, particularly the advice on the  nutritional requirements for pawpaws.

A great information resource

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In the process of researching for a post I’m planning on companion planting I came across a great information resource at the website of the University of Tennessee, Institute of Agriculture website.  They aren’t dealing solely with permaculture or organic farming, but much of the material is very relevant to those approaches.

I’ve edited the list of topics that their website links to, to make it a bit more relevant, but when you click on any one of the links below it will put you into their whole list of topics, so you can wander through it as you wish.

Companion Planting Compost Cover Crops
Crop Rotation Disease Management Fruit Production
Grower Resources High Tunnels Native Bees
Food Service Other UT info Pest Management
Seed Saving Soil Management Weed Management

Courses at Northey Street City Farm

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I’ve just received the list of courses at Northey Street City Farm in Brisbane for the rest of the year.

Two bits of good news:

First, they are offering some of their Permaculture Design Course elements as one-day courses.  Apparently people who aren’t enrolled in the full PDC can sign up for individual courses.  I haven’t seen this before, so maybe it is a new initiative by Northey Street, but anyway it is very welcome.

You can see the details of the PDC elements here, and you can sign up for individual one-day parts of it here.  The courses available as one-day workshops are:

  • Trees in Permaculture (5th September)
  • Understanding & improving your Soil (12th September)
  • Water in Permaculture (26th September)

All are full-day courses, 9.00am to 4.30pm, and cost $85 or $65 for a health care card holder.  Better get in soon if you want to attend, they are likely to be very popular.

The second bit of good news is that Tim Heard is going to do a one-day Native Bee Keeping course at Northey Street on 13th December.  Price is the same as the PDC workshops.

I attended Tim’s one-day course when he ran it in Ipswich earlier in the year.  Here’s what I said in an email to a friend:

“The workshop was fantastic.  The best workshop I can remember.  Tim Heard is not only very much a theoretical and practical expert on native bees, he’s a gifted teacher.  So much information for me to think about and digest, but I know I learned a huge amount.

“Apart from a lot of information on the types and evolution of stingless bees, design and management of hives, he split two hives in front of us, taking time to make sure everyone saw what he was doing and understood why he was doing it, and also used the hives to illustrate all the things to be aware of.  He also harvested honey from one hive (with a double honey top) while we watched”

You can book for this course here.  You won’t regret it.

A refreshingly different approach to food forests

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I’ve just been reading a post by Tom at Sustainable Veg with the intriguing title: A Forest Garden Without the Forest.

It first caught my eye because of my scepticism about permaculture “food forests” as an efficient use of land for producing our daily meals.  I’m not talking about the food forests that surround hamlets and households in Southeast Asia and other parts of the world.  I’ve had a lot of contact with these, and in general these food forests are fruit, leaf and herb production areas, often with some poultry, and which also provide shade to cool the area around the house.  Their production supplements the range of day-to-day basic foods from more distant wet or dry rice areas or upland gardens.

My scepticism relates to the tendency of many permaculture followers to focus the majority of their production efforts on food forests dominated by fruit trees of one type or another.  And there seems to be a common belief that if it doesn’t have a food forest, then it isn’t permaculture.  Permies coming into a new garden will frequently ask “where’s your food forest?”.  Of course, many people with food forests also have “kitchen gardens”, but even so, there is often a serious over-allocation of area and effort to the food forest, out of all proportion to the negligible volume of “staples” produced there and the generally low productivity per unit area.

As Tom says in another post: “Billions of people need feeding … (w)e can be an alternative, organic movement but we need to produce carbohydrate, protein and vitamin dense food, in large amounts…” (I’m not suggesting here that Tom shares my views on food forests – to be honest, I don’t know).

A view of part of Tom’s garden – click on the image to go to a gallery of photos of the garden

Tom’s describes his back garden (he also has an allotment) as “a productive, organic, kitchen garden with substantial amounts of perennial vegetables, some annual vegetables and five dwarfing fruit trees”.  But he also calls it a forest garden, and refers to his techniques as forest gardening, and for good reason.

His reason for classifying his approach as forest gardening is that he is concerned with the ecology of the garden and of the soil, and therefore uses many of the techniques of forest gardening, while stopping short of trying to create either a closed tree canopy or a climax forest situation – not least because he doesn’t have the space to grow more trees without shading out his vegetables.  Nevertheless he has adopted an impressive array of permaculture / food forest techniques –

I’ll don’t want to spoil the pleasure of reading his post for yourself, but in summary these are the forest gardening techniques he uses:

  • Vertical stacking, with three diverse layers of plants, in association with individual fruit trees.
  • The use of support plants, with half the area of his garden devoted to these, but with the difference that he composts the prunings from the support plants before putting it around the food plants.  In this way he can focus on the needs of the support plants in one area and those of the food plants in another.  I also suspect, from what he writes and from the photos in his gallery (including the one above), that many of the things growing in his food production area are supporting each other.
  • Growing a wide range of perennial vegetables.
  • Adopting a “closed loop fertility” approach whereby he grows all of the ingredients for the compost on his own land.  You can see a separate post on it here.  I find this an admirable but daunting prospect.  I certainly wish I could imagine getting to that stage on our stony dry ridge.  At the moment the bulk of our compost ingredients come from off-site (but within 10km).

Please do yourself a favour and read Tom’s article for yourself.  What Tom has done is to apply the key food forest approaches without having his productive area dominated by forest.  I’m in awe of what he’s doing and the strong ethical approach he takes, and I’ll be adopting some of his approaches as I develop and expand our food production area.

As I finished writing this I noticed that Tom has added a post about compost which gives more insights into his approaches.  Enjoy.

Lee Reich: unusual fruits, soil organisms, compost tea, moon planting and a lot more

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Just a quick one to alert you to a very interesting new podcast on the Northwest Edible Life blog featuring an interview with Lee Reich.

Lee Reich: soil scientist, horticultural scientist, author [link to leereich.com]

Reich has graduate degrees in soil science and horticulture and has worked in plant and soil research with the USDA and Cornell University, before turning to writing, lecturing, and consulting.  He has written at least nine books as well as running an interesting blog.   Because of his educational, research and practical experience in two fields which are an important part of the basis of permaculture, a lot of what he says in this interview will be of interest.  Erica, the host of the Northwest Edible Life blog, has a lively and easy to listen to interviewing style that keeps the flow of ideas coming throughout the interview.

You can also download the podcast – which leads me to the topic of mp3 player programs.  I’ve found a lot of the programs available for Macs to be a bit of a pain in the neck – and I totally refuse to use iTunes because like a lot of Apple’s market oriented software it is just too focussed on data collection.  Then I just stumbled on the fact that if I stored an mp3 file in Evernote I could also keep comments about the content of the podcast in the same in the same Note, as well as using Evenote’s very functional mp3 player straight from the note.  In fact what I do is to store the file in my General Library folder, along with pdfs etc, then link an Evernote Note to that file.

Screen shot 2014-08-11 at 3.03.12 PMEvernote is available for Mac Windows phones and tablets.  I recommend it as a great place to dump information that will be useful one day, or to keep copies of receipts (e.g. for equipment with a warranty), warranties, manuals, etc.  My only problem with it is that it can be difficult to extract files from Evernote once they are saved into a Note, but I get around that by “attaching” files to Notes (and by keeping most of my technical notes in Devonthink Pro Office).

 

Is it possible to grow vegetables using no-till farming?

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At various workshops and meetings I’ve often heard statements along the lines of “no-till approaches are all very well for broadacre cropping (e.g. grain crops), but no one uses them for vegetables” – to the point where I just assumed that there must be good reasons for not doing it.

Can it even be done, even if only by dedicated permaculturists willing to put in huge amounts of effort?  Well, yes it can, but not just through huge amounts of manual labour and on a small scale.  There are people our there successfully doing mechanised no-till vegetable production.  This article by Dr Mark Schonbeck on the Rodale Institute’s website tells the story.

Dr Ron Morse in a field of cover crops [Rodale Institute web site]

According to the article, Dr. Ron Morse, a professor of horticulture at Virginia Tech, in Blacksburg, Virginia has been working for more than two decades on soil-conserving systems for vegetable production.  This parallels efforts by Pennsylvania vegetable grower Steve Groff (in an article by Marni Katz) over the same period on his Cedar Meadow farm. The permanent cover cropping system that he has developed helped to eliminate tillage on 175 acres of pumpkins, tomatoes, sweet corn and other vegetable crops on his Cedar Meadow Farm. Not only has this approach reduced cultivation costs and improved yields and quality, it has also helped  manage the soil erosion from the farm’s sloping topography.

“You could not pay me to till my land anymore,” Groff says. “Soil erosion has gone from 15 tons per acre, per year, to almost nothing. Organic matter [in the soil] has gone from 2.7 percent 15 years ago to 4.8 percent this year, and yields have improved 10 percent.”

You can find a list of other articles about Steve Groff’s farm here.

Ron Morse (1999#) has attributed the progress and acceptance of no-till vegetable production in the US to advances in no-till planters, development of techniques for managing high residue cover crop mulches and the acceptance of (and improvements to) integrated weed management techniques.

However I think there are a lot of other factors involved, including: farmer attitudes to the “bottom line”, i.e. whether they are mainly profit-focussed or have an eye on the triple bottom line; farmers’ willingness to be different to their peers (i.e. operating outside the norm); and ability and willingness to deal with a different suite of pest problems arising from the use of cover crops.

No-till vegetable farming has been practised in Australia for around 20 years (e.g. Rogers et al. 2004#), but does not seem to have caught on widely.  However there was a study of seven trial sites at different latitudes in Australia (including one at Zeibarth’s farm at Laidley in the Lockyer Valley), published in 2006, that also reviewed a range of studies on the application of the approach in Australia.  Unfortunately it seems from a quick reading of the report that glyphosate was used to kill the cover crops at most if not all of the sites.  However, the report does include an assessment of the use of a combination of Organic Interceptor (a certified organic acceptable herbicide) and flame treatment, but concluded that only glyphosate gave acceptable long-term weed control – though clearly there are farmers in the other articles that I’ve provided links to here who are able to deal with this issue.

You can find a balanced and fairly comprehensive evaluation of the organic no-till approach here and here, providing you with a pretty comprehensive range of considerations to bear in mind when deciding whether to attempt an organic no-till approach to growing vegetables.

One thing to bear in mind though is that a lot of what has been published relates to large-scale vegetable production.  People who are looking to produce vegetables for family consumption with a surplus for bartering or giving away will be likely to have a different take on the pluses and minuses of the approach.  Steve Groff’s summary might be worth considering:

“… for the grower who does his homework, the no-till system offers significant advantages. No-till growers typically save money by reducing water use in irrigated systems, reducing cultivation equipment and fuel costs and minimizing inputs, such as herbicides and fertilizers.

In addition, Katz quotes Ron Morse who pointed out that growers often realize increased yields through soil moisture conservation and enhanced quality, particularly for crops that lay on the ground. At the same time, there are increased costs in equipment and seed for managing the cover crop.

“A grower has to be really careful to understand the system and do it right,” Morse notes. “It works if you do it right, and there are a lot of advantages.”

Unlinked Sources

# Morse, Ronald D. “No-till vegetable production—its time is now.” HortTechnology 9.3 (1999): 373-379.

# Rogers, G.S., Little, S.A., Silcock, S.J. and Williams, L.F. 2004. NO-TILL VEGETABLE PRODUCTION USING ORGANIC MULCHES. Acta Hort. (ISHS) 638:215-223

 

 

Soils ain’t just soils – and compost isn’t just compost

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Sorry for the long gap between posts.  I’ve mostly been off touring around national parks and permaculture places in northern New South Wales and southern central and southeastern Queensland with my daughter.  Some great walks in spectacular country, and some interesting comparisons between different permaculture demonstration sites.

Not long after we got back I discovered the great blog Living at Gully Grove via a guest post that its author, Chris, wrote on Farmer Liz’s Eight Acres blog about how their family uses permaculture.

When I clicked across to Living at Gully Grove, I found to my delight that, like us, they live in the hilly margins of the Lockyer Valley and clearly face some of the same issues.  It’s always great to find someone who lives in your region who is willing to share their knowledge.

That happy discovery led to an exchange of views via comments on Chris’ blog and the start of a “conversation” about sandstone soils.  As you may know if you’ve been following this blog, our place is steep sandstone country, with many rock outcrops and soil that is made up of sandstone in various stages of decomposition, and generally not more than 60-70 cm deep.  Even that shallow layer of “soil” often has at least half its volume made up of gravel and small rocks.

What passes for soil on a sandstone ridge

What passes for soil on a sandstone ridge

Early on we recognised that one of our main food production challenges was going to be the need to create suitable soil.  To that end we have done all kinds of things, including sieving the rocks and gravel out of huge quantities of the native “soil”, green manuring, mulching, terracing, etc.

So when Chris said:

Have you ever let a garden bed go (ran out of time to keep up to it) and noticed the good soil revert to something like dry potting mix?

The hardest challenge for us hasn’t been building the soil, but rather maintaining it. I notice where we have swales, the soil doesn’t need much of our attention, except where it crosses a sandstone shelf. It only takes a season of hot dry weather, to cook any good soils we don’t maintain.

I knew exactly what she meant.

For us, the challenge hasn’t only been to create good quality soil (and I can’t claim to have satisfactorily cracked that one), but to keep it in good condition.  An apparently well prepared garden bed can start the growing season with lovely fluffy, moist soil that holds together exactly right when squeezed in the hand and produces a good crop.  Then, unless it is constantly maintained, a few months later it is dry, loose and apparently lifeless.  Chris’ description of “dry potting mix” soil hits the nail on the head, particularly if one interprets it as the crap bagged potting mix that supermarkets and garden supply places sell. The plant material in these mixes is generally at best only partly broken down, and there is no evidence that there is, or ever was, life in them.

I’m no expert on soil processes, but I suspect that the coarse material in our “dry potting mix” soils is compost “residue” that has not been broken down. This is probably because (a) the soil was not sufficiently healthy initially, and in particular did not contain sufficient humic matter and soil organisms; (b) when we let the bed go there isn’t sufficient ongoing moisture in the system for biological processes to continue creating and maintaining humic matter; (c) if there isn’t a continuous cover of thick (but air and water permeable) mulch then soil temperatures rise and water content decreases; and, on a sandstone base, there is likely to be significant leaching of nutrients when major rainfall events occur. I have to say though that I have had this problem in some beds that I was actively managing, not just in ones that I’d been ignoring for a few months, but that may have been due to the leaching mentioned in the last point above.

Does the above explanation seem to match your experience / observations?

My way of tackling this problem is still evolving, but it includes:
# keeping a fluffy straw mulch cover on the soil that allows air and water to penetrate, and at the same time significantly reduces drying and insulates from overheating;
# adding green manure to the soil and digging it in. This isn’t the usual “green crop dug in” approach, but a mix of moist and drier (but still living) plant material put through the chipper / mulcher sufficient to make a 25-50mm layer on the surface, then watering it and digging it in;
# adding sieved compost “fines” (containing the humic material) to the soil;
# adding dry horse manure that has been put through the chipper / mulcher to the surface layer.  Processing it this way produces a fine, light fluffy material that holds moisture and gives the soil a great “texture”; and
# to the extent that our water supply allows (we have only tank water), keeping the soil moist, even when the area is not in production.

Good compost of course contains humic material, but can also contain a lot of woody material if you use coarse chip mulch as part of your carbon source.  This is part of the reason it’s a good idea to sieve your compost and put the finer, humic, fraction into the soil, reserving the coarser material for mulch or for feeding the next batch of compost. Unless you already have a healthy soil, there’s not a lot of point in incorporating coarse, only partly broken down, compost material into it.

If you want a good guide to how soil “works” and how to maintain its health, the best book I’ve come across is Toby Hemenway’s Gaia’s Garden (Chapter 4: Bringing Soil to Life). This is by far the best and most practical permaculture text I know. The other good source for soil matters is, perhaps surprisingly, Harvey Ussery’s The Small-scale Poultry Flock (pages 137-144 for soil matters). We have a pretty comprehensive permaculture / organic library but these are the two books I go to first when I have a question, and I seldom need to go past them.