Green Manures

Green manures are grown to improve soil fertility. They are one of the cheapest and most sustainable ways of improving your soil. Typically green manures are planted over winter.

Cut your green manure down and turn in with a garden fork either when any flowers start to appear or about four weeks before spring planting.

Our green manure bags packed up ready for market

Our green manure bags cover around 5 square metres. They are made up of a combination of nitrogen fixing plants (tic beans, blue lupins and grey peas), fast growing winter plants (mustard and oats) and plants with deep roots to mine the subsoil (ryecorn).

Why Mulch?

Mulching is one of the best things that you can do in your garden. It saves you time by reducing the need for weeding and watering. It also improves your soil.

This photo demonstrates the benefits of mulching. One half of the bed was mulched for the first 2 months and the other side, with the smaller garlic, was not.

Mulching does this by suppressing light and therefore stopping weeds from germinating around your plants and competing for nutrients, water and light. It saves water and reduces the need to water by reducing the rate of evaporation through creating a barrier to evaporation. I rarely water my vegetable garden once seedlings are established.

If plant based mulch is used then soil health will be improved. Organic mulches break down slowly adding organic nutrients to the soil. This Improves soil structure and encourages earthworms and microbes that are important for your soil health.

I always use organic mulches in my vegetable garden. My favourite mulches are sugarcane, pea straw. One of the few downsides of mulching your garden is that mulch steals nitrogen from the soil in order to break down, leaving your soil short on nitrogen. This affect called Nitrogen draw down can me avoided by first applying a tight fistful of blood and bone to the soil surface before laying down the mulch.

My favourite mulch is organic sugarcane mulch. It is easy to use as it is finely chopped and so soft on the hands. It also looks nice, is readily available at most garden centres for no more than $20.

It is really important to mulch an area as you clear it of weeds. Do not leave time between weeding and mulching. This allows the soil surface to crust and seeds to germinate. You apply mulch thickly around 7cm thick in for cleared and thicker if suppressing existing weeds.

Crop Rotation Basics part one, Soil based pathogens

Crop rotation basics consist of designing a planting rotation based on knowing the affects of:-

1. Soil based pathogens
2. nutrient  deficiencies
3. heavy and light feeders

This article will cover the first topic only.

Soil based pathogens

Some plant families are affected by pathogens that build up in the soil in response to its food source i.e. that plant family. Planting members of that family in the same soil repeatedly provides the conditions for that associated pathogen to multiply its population to levels that cause noticeable distress to that family member. Starving that population of pathogens before it numbers increase to problem levels is how you manage soil based pathogens naturally.

Plants families which are affected by soil based pathogens to my knowledge are

• Brassica
• Solanum

Brassica also known as the cruciferous family due to the flowers resembling a cross, represent a large portion of cultivated food consists of

·        Horse radish

·        Land cress

·        Ethiopian mustard

·        Kale

·        Collard greens

·        Chinese broccoli

·        Cabbage

·        Brussel sprouts

·        Kohl Rabi

·        Broccoli

·        Broccoflower

·        Broccoli romanesco

·        Cauliflower

·        Wild broccoli

·        Bok Choy

·        Komatsuna

·        Mizuna

·        Mibuna

·        Rapini (broccoli rabe)

·        Chinese cabbage

·        Turnip

·        Rutabaga

·        Canola rapeseed

·        Mustards

·        Tatsoi

·        Rocket

·        Garden cress

·        Watercress

·        Radish

·        Daikon

·        Wasabi

The soil based pathogen that affects this family is called club root

 As the name suggests the roots of the plant swell with infection causing poor uptake of nutrients. Once club root takes hold in the soil it can take in excess of ten years for the pathogen to decline to non affecting levels. Managing the problem once it is present requires starving it of any member of the cruciferous family for a minimum of 4 years or longer if possible. A natural soil soak which may help kill off this pathogen while the soil is being "rotated" consists of rhubarb leaf tea. Application is every three months for a few years and is applied as a soil drench i.e. poor a bucket of the prepared tea on the affected soil.

Solanums is the next most cultivated family in most backyards and consists of

• Chilli
• Eggplant
• Goji berry
• Potato
• Sweet peppers
• Tamarillo
• Tomatillo
• Tomato

The soil based pathogen that affects this family is potato blight. While this blight mainly affects potatoes, growing any member of its family repeatedly in the same soil without a four year rotation gap may lead to pathogen build up to problem levels.

For more detailed info on how to avoid and recognise potato blight follow this link.

http://gardenofeaden.blogspot.com/2009/03/organic-and-cultural-control-of-potato.html

Below is a image I derived from analysing ABC gardening website

PH and nutrient availability

Time spent improving the nutrient levels of your vegetable garden can amount to not much if one soil PH is out of whack. The PH level decides what nutrients are available to the roots of plants. The PH range which most plants thrive in is between 6 and 7.

Testing your soil takes about 30 seconds and a  PH soil test kit costs about $17 dollars and can be purchased from  me and most garden centres.

The test is as easy as getting a thumbnail sized piece of typical soil drip a few drops of purple liquid on it then squirting a bit of white powder on to the same area. Check against the colour chart to see what your sample PH is then relate that number to the next image The chart below has a green band which indicates the range which most plants thrive. When the soils PH is outside of this range some of the nutrients needed by a plant are bound up and unavailable to the plant even if that nutrient is present in large quantities.

dolomite is used to increase the PH of your soil

sulphate of potash is used to decrease the PH of your soil

Always adjust the soils PH slowly over time using no more than a hand full per square metre per three months.This slower rate of adjustment avoids shocking plants and soil microbes alike. Depending on the crop grown adjust the soil PH  as needed. next time you  are ready to plant, Google the PH range of your next crop and improve your gardening experience.

Preparing beds for spring planting with natural fertilisers

Vegetables can be grown in soils that have not been improved with fertilisers and other soil additives but the size and quality of the resultant crop will be less than if the plant is grown in soils which have been enriched with suitable fertilisers.
The kind of fertilisers I use in my own backyard consist of animal manures, spent mushroom grow bags, home made compost, blood & bone powder and dried, chipped seaweed. Soil amendments used consist of dolomite powder or sulphate of  potash.http://hobartkitchengardens.blogspot.com.au/2010/09/ph-and-nutrient-availability.html
Animal manures suitable for direct contact with plant roots include aged bags of sheep and cow manure.Bounce Back is a pelleted manure blend which is certified organic and very convenient to use. 20 kg bags of bounce back can be brought from Waratah.wholesale 1 Tara St South Hobart for $11.30     Mushroom bags can be purchased from smaller nurseries in open top bags much cheaper than the sealed 20 litre bags sold in chain stores like Bunnings and K&D. Spent mushroom bags can give you a bonus crop of mushrooms if you cover the garden bed with straw after incorporating the mushroom bags into the top ten centimetres of soil, just keep up the water and wait for the mulch to rise.
Tasmanian made100% pure  Blood & bonemeal can be purchased from Waratah or Roberts rural supplies in 25 kg bags for $30.50. Most blood and bone products on the market are only 60% pure with sawdust making up the rest.
Dried seaweed  chips can be brought from Hollanders Imports, 87 Brooker Highway Hobart just before the ABC roundabout.

Ideally these fertilisers would be incorporated into the top 20 centimetre of the garden bed four weeks before planting out but who is that organised. Roots of plants can be burned by chicken manure which is best used as an ingredient in compost, but the inputs mentioned above can be incorporated on planting day without negative affect.

Amounts spread and frequency of application depend on how poor your soil is to start with and what you want to grow. A hand full of manure pellets, blood and bone and seaweed per square metre is good every 6- 12 months  will feed most plants. If you are using sheep Manure or mushroom bags  then a bag of each per three square metres of garden bed per year will see fantastic crop production. When growing root crops like carrots and parsnips or onions and garlic wait till after a heavy feeding crop like cauliflower or corn has taken many of the nutrients out of your soil, otherwise carrots will fork and onions will not store well.
P.s.
prices may have gone up since my last update.