The Real Dirt on Nitrogen Fixation

This broad bean plant is fixing nitrogen in the soil right? Well...... probably not. Here's why.


You may have heard that peas, beans and other leguminous plants fix nitrogen. This means they have an innate capacity to absorb nitrogen from the air and convert it to a plant-available form in the soil. Right? Well... not quite. Shattered? I was, when I first found this out, so I thought I would finally reveal the best kept secret on nitrogen fixation.

The harsh reality is that if you sow a patch of broad beans in your vegetable patch, they are very unlikely to be fixing nitrogen in the soil. But why?

Only specific types of bacteria around plant roots have the ability to convert nitrogen to a form that is 'bio-available' to plants (ie. a form that plants can eat). To complicate things, there are many different types of nitrogen fixing bacteria, each only fixing nitrogen for a select few plants. The likelihood of having exactly the right type of nitrogen-fixing bacteria in your soil for your specific plant is very low. This likelihood is further diminished if the soil has been tilled, plowed, or brought in from elsewhere.

Let us remember that the way we traditionally grow veggies in rows is a very 'unnatural' system: they do not form the complex inter-relationships plants form in a forest ecosystem. 

Most organic, regenerative, biodynamic farmers, and some permaculturalists know this and inoculate their seeds and/or soil with the correct bacteria and fungi. These days, it is possible to buy specific natural inoculums for your cover crop seeds to ensure they will be fixing nitrogen in the soil. This is something I would suggest if you are constructing a Permaculture food forest, as this will ensure your nitrogen-fixing forest layer is actually doing just that: fixing nitrogen. Green Harvest sell fantastic cover crops and green manures with corresponding inoculums.

Biodynamic agriculture does this by including specific plants in compost preparations. For example, yarrow roots secrete substances that attract a type of nitrogen-fixing bacteria called Azotobacter. When yarrow is composted and used in your garden, this bacteria will be present in your soil. All plants used and composted in biodynamic preparations accumulate specific nutrients, fungi and bacteria in their roots, leaves and flowers. These are essential elements to have in your soil to ensure a healthy food growing system.

But how do you know whether or not your plant is fixing nitrogen? Gently have a look at its roots. If your plant has little white nodules on its roots, you're on the right track. However, to make sure nitrogen fixation is occurring, break open the nodules. If they are red inside, your plant is fixing nitrogen. Hurray! In the field, small nodules can be seen 2-3 weeks after planting, depending on legume species and germination conditions. When nodules are young and not yet fixing nitrogen, they are usually white or grey inside. As nodules grow in size they gradually turn pink or reddish in color, indicating nitrogen fixation has started. The pink or red color is caused by leghemoglobin (similar to hemoglobin in blood) that controls oxygen flow to bacteria.

So there you have it. The real dirt on nitrogen fixation.


To Weed or Not To Weed?

Chickweed: delicious salad green, medicinal tea plant, photosynthesizing living mulch.


In my years of growing food, I have always been conflicted with the issue of 'weeds.' I am always amazed by how much passion, anxiety, and even fear we attribute to some of these plants. According to the Oxford dictionary, a weed is "A wild plant growing where it is not wanted and in competition with cultivated plants." I often find fellow gardeners and growers obsessing over the possibility of weeds "taking over" as though I would walk out to my garden one day and find that the chickweed monster had gobbled up everything.

My Permaculture background has given me quite a different outlook on many 'weeds'. In Permaculture, we look at natural succession in a forest ecosystem, and where different types of plants sit within it.

Most plants we commonly refer to as 'weeds', such as grasses and ground creepers, are regarded as 'pioneer plants.' Their function is to step in right after a disturbance (such as a bushfire for example) and quickly colonise the area, covering, protecting the soil, quickly filling it with stabilising roots, encouraging beneficial microbes and earthworms back, and preventing further erosion.  'Weeds' such as dandelion, have long taproots that mine for nutrients deep in the soil profile, stimulating bacterial, fungal, and earthworm activity, which ultimately creates more organic matter. So why on earth don't we want them around?

Cameron and I examined our vegetable garden this morning, and looked at the chickweed growing around our kales. Our soil is quite sandy, and we have been doing everything possible to build organic matter and stabilise soils. So we asked ourselves the following question: do we pull the chickweed and mulch with sugarcane, or do we leave the chickweed as a 'living mulch'? The answer came quite quickly. This living chickweed is sequestering carbon from the atmosphere, has roots that stabilise sandy soils and promote microbial activity. Its root system, like that of many pioneer plants, is very shallow and will not compete with the kale around it. It can easily be harvested gradually when needed (chickweed is delicious in salads), and therefore has many, many more functions than any dried mulch.

Chickweed is quite an amazing plant, botanically named Stellaria media and also commonly called Starweed. Eaten fresh, it is a mineral and vitamin rich herb, like our dear nettle and parsley, and builds strength and wellness especially in the convalescing, elderly or people with multiple food allergies or sensitivities and nutrient deficiencies. Its leaves are mucilaginous and heal and sooth inflammation especially in the respiratory tract and tummy. Chickweed can also be drunk as a fresh or dried herb tea or decoction daily as a tonic when you’re feeling depleted or inflamed. chickweed also aids the bio-availability of nutrients into the cells and help to break down unhelpful bacteria, toxins and mucous in the body.

Externally chickweed is antipruritic, meaning it relieves itching. It is useful as a poultice for treating wounds or ulcers, as well as skin conditions that are inflamed, itchy and painful.

Could our obsession with 'weeding' and 'weeds' be fueled by the commercial gardening industry, who want us to buy their sprays and products? Personally, I've adopted a more relaxed approach to unwanted plants, and see removing some of them occasionally as simply part of the wonderful activity of gardening. Apart from the amazing functions they perform mentioned above, most of them are also highly nutritional and medicinal, and there is very little chance of weeds 'taking over' as long as you keep a regular eye on your garden.

Our chickweed/kale bed (back)

Our chickweed/kale bed (back)

Winter Growing and Musings on Social Resilience

Our Lyttleton garden is chugging along, relatively slowly at the moment. Our sugarsnaps and snowpeas are loving the cold, and so are the broadbeans and radicchio. Potatoes need to be kept warm with straw and hessian in order to keep producing tubers, but we are able to keep them going here in the mid-mountains, where the climate is considered warm temperate, bordering on cool temperate. 

In the lower Mountains, where the climate is warm temperate, bordering on subtropical, potatoes are going strong, my sweet potatoes don't seem to want to die back, but gingers and turmeric have finally gone to sleep.

In the cold temperate upper mountains, apple, stonefruit and cherry trees are getting plenty of chill hours to be setting fruit. Only hardy, frost tolerant veggies are growing at the moment.

The incredible diversity of climates in the Blue Mountains is an incredible asset, as it means we can grow a diversity of foods within a relatively short distance. Our backyard growers from the lower Mountains are bringing us ginger and turmeric at the moment, mid-Mountains growers are providing us with loads of citrus, whereas upper Mountains growers are keeping us stocked with apples. What a wonderful, resilient space we have the potential to create!

The financial, environmental and social benefits of growing local organic food are quite apparent: less food miles, more earth stewardship and building social relationships among locals. Our 'office cubicle' way of living is making us lonely, depressed, and anxious, and people in our peri-urban environment are slowly reacting to this and things are changing. Social media groups are re-establishing local swap and barter systems, and some of us are keen to take this back to our streets and local spaces.

I see this at Springwood Community Garden, as older members, who walk up the hill from the local aged care facility, bump into young mums and/or dads, who feel they need to be out and about. The inter-generational relationships I have seen come out of a simple communal garden space are immense and important. We have forgotten how important inter-generational contact is for our wellbeing.

In our little veggie patch and shop, we are striving to empower people to grow their own, to come to our meet ups and exchange knowledge and experience, to come to their local shop rather than a supermarket, and get food produced as locally as possible.

Tea and Daisy Chains

roman chamomile is a wonderful ground cover plant

roman chamomile is a wonderful ground cover plant





Here is our naturopath Sarah Mann's recipe for a chamomile compress:

Roman Chamomile wrap for painful cramps in the tummy or for earaches





Perennial Edibles: Low Maintenance Food Growing

Let's face it, growing annual vegetables is quite a bit of work. It requires dedication, persistence, and is sometimes risky business! How many times have you carefully and lovingly looked after your beloved broccoli, only to come out to the garden one morning and find it had been devoured by rats, birds or possums?

This is why it's a good idea not to put your eggs in one basket by growing a variety of edibles and including perennial edibles into your productive garden design. As opposed to an annual plant, which has a life cycle of six months to a year, perennial plants can last 5 to 15 years or more! There are hundreds of varieties of perennial edibles, many of which are described in a wonderful book written by Eric Toensmeier entitled Perennial Vegetables, which I really recommend.

As chance would have it, you already are growing some perennial edibles in your garden like rosemary, lavender or thyme. You may have inherited them from your landlord or the previous owner of your home and they happily provide you with a constant supply of herbs (and provide the bees with wonderful nectary flowers) year after year. What giving plants they are!

As it turns out, perennial vegetables work much in the same way. The wonderful thing about them is that they are often very hardy and low maintenance. Many thrive in part shade, so are a wonderful option in a shady garden. You plant them once and they will provide you with fresh food season after season.

Let's go through a couple of our favourites:

- Salad burnet is a wonderful perennial, peppery, leafy salad plant that will provide you with a constant supply of salad greens all year long for years to come. It is a great ground cover layer in a permaculture food forest and is very easy to grow. That possum we mentioned above can literally eat it right to the ground, and burnet will come right back and grow more vigorously than before!

- Lovage is a wonderful celery substitute as you only need one stalk of lovage in your stew to replace three stalks of celery!

- Perennial leeks are fantastic as they provide you with a constant supply of leeks (smaller than traditional ones, but much tastier) by constantly sending out new baby leeks that you can divide and re-sow.

- Gotu kola is a great bog plant (for boggy, shady areas in your garden) said to alleviate and prevent arthritis.

- Asparagus can live up to 20 years! Now is a good time to plant asparagus crowns. I would plant about four for one household. They will start producing a good amount of spears in their second year, die back every winter, and come back every spring!

- All members of the mint family are wonderful medicinal edible perennials, although you may want to plant them in a pot as they do tend to take over. One of these, which we have a lot of in our vegetable garden, is lemon balm. It is one of our Naturopath Sarah Mann's favourites. We have a Holistic Gut Health Weekend coming up in our workshop space and lemon balm is a herb that will feature for its ease of growing in the Blue Mountains and it’s incredible help restoring gut health.  It has the most beautiful, warm, citrusy and refreshing scent. A low mood or lethargy is transformed with it’s beautiful aroma, lifting and strengthening the spirits and sharpening the mind. Lemon balm is a powerful anti viral and anti microbial, sweeping the gut clear of unhealthy bacteria and bugs while nourishing and repairing the gut. It is warming, calming and enlivening, bringing the gut into a supple and supported responsiveness and providing a landscape for healthy gut flora.

Perennial herbs, vegetables, and fruit (most fruits and berries are also perennial of course) play an important role in a diverse, productive garden providing long lasting yields of food and medicine, nectar for beneficial insects and different edible 'layers' in a food forest ecosystem.

Harvesting our Turmeric

Winter is settling in. Our turmeric and ginger are dying off, which means it's time to harvest! We will talk about how incredibly beneficial turmeric is a little later, but first let's talk about growing your own. Turmeric is a plant you can grow all year anywhere in the Blue Mountains. Surprised? Here is the trick: as your plant dies back around this time every year, put one rhizome in a pot with a good organic potting mixture and keep it indoors. It will shoot into a new plant, which will be very happy if kept warm indoors. It won't mind filtered light and shade and makes a beautiful indoor plant, which will turn excess carbon into oxygen and purify the air. If you wish, plant it out as soon as it is reliably warm outside and it will grow into a bigger plant, which means more turmeric rhizomes!

Turmeric has attracted much attention in the scientific research world in the last two decades. It is part of the Zingiberaceae family alongside ginger, galangal and cardamon. Ithas been used for much of human history for many things, as a dye, a spice, a perfume, in religious ceremonies, as a paint and a symbolic adornment, in festivals and in traditional and modern medicine. The rhizome is used and it is a bright, warm, golden colour.

Medicinally, turmeric has many actions and qualities. Curcumin is a constituent of turmeric that has been studied extensively in the treatment of conditions such as Alzheimers disease, diabetes, cancer, autoimmune disease and arthritis. It is a potent antioxidant and has anti inflammatory, anti platelet, antibacterial, immune enhancing and anticancer actions in the body.

Turmeric as a whole rhizome stimulates digestion by encouraging the flow of bile and supporting the liver to function optimally. It provides warmth to slow, sluggish digestion. It provides relief to digestive discomfort especially where pain and inflammation are involved, like stomach infections, ulcers or stress related upset. It is used for skin conditions like eczema and psoriasis where sluggish digestive and liver processes contribute to the condition. Curcumin is also protective to the gut and helpful when ridding the gut of fungal overgrowth like candida, bacteria or parasites.

Curcumin is a great antioxidant and is used in heart conditions and diseases, cholesterol and lipid disorders and diabetes. It has anti platelet activity so shouldn’t be used therapeutically alongside anti platelet or anticoagulant medicines like aspirin and warfarin. It should also be avoided one week prior to surgery for this reason.

Curcumin is really a hero when it comes to inflammation, chronic or acute. It is used for people with arthritis, rheumatism and Alzheimers disease and inflammatory skin conditions. Curcumin also protects the body from tumour growth and development. Turmeric is a herb that is supportive in our day and age for long term health and wellbeing.

Turmeric can be added into the diet very easily (and enjoyably!) by including it in warm drinks like golden milk, curries, bliss balls, or added to rice to make it golden. In Pantree we sell the beautiful Rooibos Turmeric Chai by Mayde Tea, a beautiful tea for the winter or chilled in summer.  Turmeric can also be taken in tablet form, usually in its isolated Curcumin state. It is important to look to traditional use when it comes to herbal medicine and not only isolated active constituents. It is well known scientifically that black pepper added to turmeric enhances the bioavailability of medicinal properties to the body by a good scientifically significant mile, as do fats. So a traditional indian curry with turmeric, black pepper and a long list of other gorgeous spices aswell as coconut cream or oil is a perfect medicinal meal. When you are adding turmeric to a recipe also add a crack of black pepper to ensure you’re getting the most from your dear herbal friend Turmeric.