Polyculture Trials - The Results

Paul Alfrey - Balkan Ecology Project
Thursday, 22nd December 2016

Paul Alfrey and his family run the Balkan Ecology project. In their home garden, they also run polyculture experiments, timing and measuring everything, to get the best results. Here is the 2016 trial results.

For the previous three years we have been testing the practice of growing vegetables and herbs in polycultures (or what is known as guilds within permaculture circles). We have been using our home garden for these tests and recording the inputs and outputs from the growing seasons. Our aim is to discover whether or not growing in polycultures offers benefits over conventional methods of growing, and to see to what degree we can obtain good yields of nutrient dense food whilst providing habitat for garden wildlife.

What follows is a description of the garden layout and planting scheme, an overview of our cultivation practices, the results from year three of the study, our record keeping methods, and some notes and observations from this year.

If you would like to see the results from previous years click below:

Last year we started a scaled up version of this study looking at polyculture growing for a market garden. The results from year 2  will be coming soon. You can read more about that study here

Garden Overview   

Climate: Continental Temperate
Latitude: 42°
Elevation: 580m
Average Annual Rainfall: 588.5mm
Co-ordinates:42°42′N 25°23′E

Garden Layout  

Garden area: 66.5m2
Cultivated beds area: 36m2
Paths: 30.5m2

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The Polyculture Planting Scheme  

Below is a typical representation of the polyculture planting scheme within a bed.
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In 2016 the following plants were grown in the 6 beds (36m2)

11 x Tomato - Solanum lycopersicum 'Black Krim'
11 x Tomato - Solanum lycopersicum 'Tigerealla' 
11 x Tomato - Solanum lycopersicum 'Mixed Saved Seed'
11 x Tomato - Solanum lycopersicum 'Rozova Magia'
11 x Tomato - Solanum lycopersicum 'Anna Russian'
11 x Tomato - Solanum lycopersicum 'Ukranian Purple'
66 x Basil - Ocimum basilcium 'Sweet Genovese'
27 x French Beans - Phaseolus vulgaris 'Cobra'
27 x French Beans - Phaseolus vulgaris 'Local'
2 x Courgette - Cucurbita pepo 'Black Beauty'
4 x Yellow Bush Scallops - Cucurbita pepo 
6 x Butternut Squash - Cucurbita pepo 'Waltham Butternut'
4 x Swiss Chard - Beta vulgaris subsp. cicla ' Rainbow Chard '
4 x Sunflower - Helianthus annuus 
12 x African Marigold - Tagetes erecta
12 x French Marigold - Tagetes patula
6 x Pot Marigold - Calendula officinalis

The table below shows the floral species composition of each bed including the different cultivars and the dates that the plants were sown or planted. Beans, courgettes and winter squash were sown directly into the beds, tomatoes, basil, chard and marigolds were grown from seed indoors reared to approx 15cm tall and  planted outside around mid spring. Sunflowers and pot marigolds are self seeded.

Other plants such as volunteer nasturtiums were also growing within the beds. The yield of these plants are not considered in these records. Also not included are the native wild plants that are encouraged to grow around the perimeter of each bed. Many of these plants provide excellent fodder for our chickens and rabbits as well as mulch material when chopped and dropped on the beds.

2016 - CTB Management and Yields : Plant List

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Polyculture Cultivation Practices  

In the early spring when the temperatures are warm enough for the chickens to be outside during the night, we place a 1 x 3m bottomless chicken coop with 8-10 hens inside onto one half of a bed. The chickens will live there for 3 or 4 days and each day we throw them in kitchen scraps, grain and weeds. The chickens relentlessly scratch among the soil and mulch picking off the eggs of slugs and larvae as well as pupae of various arthropods. They also forage for seeds in the soil and thereby reduce the emergence of undesirable plants in the bed. The chicken's scratching mixes up the organic matter we throw in daily and the birds contribute a valuable supply of droppings as they go.
After 3 or 4 days we move the chickens onto the next half of the bed and the process repeats. The area the chickens have just moved from is forked over, soaked well (or we wait for a rain) and usually 20 L of compost per 1.5m length are applied i.e 80 L per bed). A 20cm layer of straw mulch (approx 3/4 of a bale) is then laid to cover the surface. The mulch provides good habitat for toads and lizards (in the spring, summer and autumn) which are well positioned to pick off any slugs that venture in for the young seedlings.

Once mulched the stakes for tomatoes and beans are put into position. Large reliable germinating seeds such as beans and squash are sown directly into the beds by pulling back the mulch, making a small nest adding 3 handfuls of potting mix (50% compost 50% river sand) and sowing the seeds directly into the mix. All other plants are reared in pots and planted into the beds when approx 15cm tall and when the weather is suitable. Any weed plants that grow around the edge of the beds are cut back before they set seed and used as additional mulch throughout the year. Weeds growing within the bed are treated the same way. Note that weeds are not uprooted only cut to ground level. The roots are allowed to decay in the ground or left to regrow until they are again ready to "chop and drop".

Around July the vegetable and herb plants are all well established with little room for weeds. The attention the beds require after July is mainly irrigating and harvesting until October.
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The polyculture in the summer
When the last of the harvest is out of the beds, the stakes are removed and if warm enough the chickens are brought in for another 3 or 4 days to pick through the vegetation. None of the plant material is removed from the beds. What the chickens leave behind is cut into small pieces and applied to the surface as an overwinter mulch. In November, garlic is planted in some of the beds. November sown garlic will normally mature in June, however we use the small bulbs that are not worth planting as main crop garlic and harvest them in March like spring onions before the chickens go on, providing a deliciously fresh treat in early spring.

Soil Analysis

Each spring and autumn we obtain a soil sample and send it to NAAS of the Ministry of Agriculture and Food. We can see from the samples rising levels of essential plant nutrients and check our pH levels are within the optimal range for vegetable production.

Year 3 Results in Summary

This year we harvested 168kg of vegetables including tomatoes, basil, beans, garlic, winter and summer squash, chard and sunflower heads, a 51kg decrease on last year's total.

The time spent on this garden, including propagating all the plants from seed, preparing the beds, tending the plants, irrigating and harvesting amounted to 57 hrs and 20 mins from March - October. We used 480 L less compost this season than last season.


Results: Inputs and Outputs 

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Table summarizing input and outputs from October 31st 2015 - October 31st 2016


All produce was weighed directly after harvest and unless otherwise stated, all of the produce recorded was in excellent condition and fit for market. Produce not fit for market was composted or fed to our animals and is not included in these records.

Record Keeping Methods  

The tasks were predominantly carried out by one person, either myself, my partner Sophie or one of our boys Dylan and Archie. A timer is started just before the task starts and stopped when the task is complete. On a few occasions two people were working on tasks at the same time, namely erecting the stakes and planting the garlic. These occasions are recorded in the management sheet of the record keeping spreadsheet 2015 (in the 'notes' row).

In 2015 we established base times for garden tasks that are carried out each year and we extrapolate from this results for future records. Some tasks differ in quantity each year such as irrigation, mowing and harvesting and we account for these separately. 

Irrigation 

Our irrigation system is unique to our garden in that we flood irrigate using a mountain stream, however I estimate the irrigation needs of the polyculture to be 20 L per m² i.e. 120 L per bed or 720 L for the entire garden applied once a week in the absence of rain (normally July - September). The time taken to apply 120 L per bed is estimated at 10 minutes so that's 60 mins per irrigation session. This year we experienced a very dry summer with a period of 13 weeks without significant rain. During this period, irrigation was practiced once per week.

Mowing

The time for mowing is estimated to be 10 minutes. During dry seasons less mowing is required whereas during wet seasons more mowing is required. This year we mowed the pathways seven times.

Harvesting  

Harvesting times are recorded along with other garden tasks such as tying tomatoes and weeding, so we don't have a base for this task. For this year's results we used last year's figures, but it would actually be less as the total produce harvested is 51kg less this year. A harvest base time is required for future records.

Notes and Observations

  • Farm Ducks were free ranging in the garden from July - mid October and often foraging in the straw. This breed of duck (some type of mallard breed) caused little notable damage in the garden but probably made it less likely for toads and lizards to hunt in the straw. 
  • The decrease in production this year may be attributed to the below: 
  1. We did not add the usual 480 L of compost this year as the soil results showed ample nutrients for vegetable production. 
  2. A cold and wet April and May meant that many squash and beans did not germinate. This resulted in less producte than would be expected. Next year we will be growing these plants in starter trays and planting out when the weather conditions are favorable.  
  • The market value of the produce is estimated based on average market prices from the food coop Trustika.  It is not what we actually sold the food for, as much of the food from this garden was consumed by us or preserved.
  • Our low expenses are attributable to the fact we grow our own plants from seed, make composts and sowing mediums, grow summer and autumn mulch and save seeds from plants that do not readily crossbreed such as tomatoes, basil, marigolds and beans. We also provide our own support materials (tomato stakes and bean poles). Time taken to make composts and harvest support stakes are not included in the records.

For the full article, visit: http://balkanecologyproject.blogspot.co.uk/2016/11/polyculture-trials-2016-home-garden.html

More from the Balkan Ecology Project:

A guide to Japanese quince

All you need to know about figs

Using perennial polycultures to create mulches and fertilisers

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