Growing Saffron in Canberra Region

I first planted saffron (Crocus sativus) around 2018, and after growing saffron continuously for several years in the Canberra region, I have learned a few things about what works (and what didn't).  In late April this year my saffron started flowering.  It normally flowers around Easter for me, the last two years my saffron has been a little later than normal. 

I find saffron easy to grow organically.  Saffron seems especially well suited to the conditions of the Canberra region.  

I have received a few questions about saffron, plus it flowered recently, and I thought I would write another blog post on it. 

Saffron crocus flower pulled apart to show my kids

Why I'm hesitant to write this post 

Last time I wrote a blog post on saffron my blog received several unpleasant comments such as the one below.  Other messages were calling me names and other messages telling me to kill myself.  

At the time, I didn't know who was sending them, or why.

One comment left on my blog

Without going into detail, I later came across information that caused me to believe some of the comments may have been connected to people I had known through a baptist church I attended several years earlier.

Following the influx of hostile comments, I changed my blog settings so only users with Google accounts could leave comments.  After making that change, the hostile comments have stopped.  

I was disappointed with how my concerns over this and other serious allegations of misconduct were not investigated by the Baptist Standards Unit.  My personal experience left me feeling that concerns about controlling behaviour and unhealthy leadership dynamics are not taken seriously at an institutional level.  

While I doubt people will continue to leave comments like the one above with their names attached, and I doubt the comments were in any way related to saffron, I still feel hesitant to write a blog post about saffron.  Even thinking about my saffron flowering fills me with anxiety.  It's interesting how the mind works.  

Saffron threads - the darker coloured area is strongest

Why the Canberra region is ideal for growing saffron 

The Canberra region is known for having hot dry summers, and cold winters.  Saffron performs best when given hot dry summers when the corms are dormant, and cold winters when the plants are actively growing.  Sounds like a good match. 

The corms need to be dry when dormant, or they rot.  Heat when they are dormant also helps them flower better, I will explain that more below.  I have no idea how the cold winters while they are actively growing helps them, but I have cold winters and they perform well for me here.  

Saffron plants grow from corms.  A corm is similar to a bulb in many ways, and many people would use the terms interchangeably.  

Saffron is a sterile triploid, meaning it can not produce viable seed.  As saffron can't produce seed, it must be grown from corms.  Luckily, saffron corms are simple to grow, and they divide reasonably quickly. 

Saffron threads stored in a little glass jar

Saffron corms are dormant over summer, they sprout in autumn and grow during the cooler seasons.  Sometimes saffron sends up a flower before the foliage, other times they send up leaves first and then flowers.  Both are fine.  

If the corms are too small they may not flower that year.  Look after these small corms, and they will be big enough to flower the following year. 

When saffron flowers, it tends to send up several flowers, and it does this across a few different days.  You have to keep an eye on your saffron patch during the season otherwise you may miss the flowers.  

Fresh saffron threads before drying

What saffron plants look like 

The leaves of saffron plants look a bit like grass.  When not in flower, saffron is uninteresting to look at, but it doesn't look bad.  It just kind of blends in.

I don't have enough space to devote to saffron.  I grow some saffron in the garden among berries and things, and some saffron in pots of soil.  Both perform well for me. 

When planting saffron, if it is planted too shallow it tends not to flower.  Shallow planted corms (10cm) usually divide into many small corms.  Deep planted saffron (15-20cm) tend to flower better, and divide into fewer, but larger corms.  

I grow a bit of both, the deeper planted ones give me more flowers that year and the following year, the shallow planted ones increase the numbers. 

Saffron plants sprouting 

This year, mostly due to over crowding, I did not get a lot of saffron flowers.  As you can see, this pot has far too many corms.  I have a few pots of saffron, most are crowded.  I ran out of space and decided it was better to crowd them for a year or two rather than not planting at all.

The saffron planted in my garden are flowering, and some of the larger ones in the pots are flowering, but most of the container grown saffron did not flower this year.  

I top dressed these pots with compost.  This will feed the corms and hopefully they will grow fat and be large enough to flower next year.  

Saffron top dressed with compost 

Saffron plants look like grass

Saffron corm flowering size 

Saffron corms flower when they are large enough.  The way I tell if a corm is flowering size is by measuring their circumference.  I don't measure the diameter, it is too unreliable, I measure the circumference. 

Saffron corms are not very round, they have flat edges and things, so measuring the diameter doesn't work.  Instead, I wrap a piece of string or something around them and then measure the string, that gives me the corm's circumference.  

Saffron corms with a circumference of 7cm or more will flower, anything smaller may not flower that year.  

Saffron corms are dormant over summer

Saffron needs heat when dormant 

Many perennial vegetables suffer from virus load.  Things such as potatoes have diminished yields, and can eventually fail completely, unless they are cleared of viruses.    

One study identified 17 viruses that affect saffron, and other studies suggest saffron yields may be decreased by several more viruses.  As saffron can't be grown from seed, virus load could potentially be an issue. 

Luckily, the traditional way to grow saffron effectively eliminates viruses.  One study states that saffron viruses can be eliminated by thermotherapy, this is where the corms spend 30 to 40 days at 35 °C.  You could place corms in an incubator for 40 days to eliminate virus load, but this can be avoided.

Saffron needs a hot dry summer to flower well, this is likely because it is destroying the virus load.  

When growing saffron, some years I leave the corms in the soil, others I dig and lift them.  I store the lifted saffron corms in a mesh bag in my garage.  Over summer it is hot in my garage, it reaches over 35C, and while the temperature drops at night it rises the following day.  Most summers the corms in my garage get more than 40 days of these high temperatures, which naturally eliminates virus load without the need for an incubator.  In the Canberra region, these higher temperatures are reached naturally over summer.  

My saffron usually flowers well each year, I guess this is because it has had the virus load largely eliminated through storing the corms hot and dry.  

Saffron flowers are pretty, and they smell nice

Increasing saffron yield

Interestingly, I've read a few studies such as https://pmc.ncbi.nlm.nih.gov/articles/PMC6604984/ which indicate natural soil bacteria can help saffron yields increase.  

Plant Growth Promoting Rhizobacteria are natural soil bacteria.  Some species, such as Curtobacterium herbarum, are demonstrated in several studies to increase the number of saffron flowers and significantly enhance the length of the saffron filaments. 

I grow everything organically, and have a large range of plants growing.  While I am not sure if C herbarum is present in my soil, there is a good chance it may be.  It is present in the Canberra region, and given the wide range of plants I grow there is a good chance it has inoculated at least one of them, and should be able to spread from there to my saffron.  

If this species is present, research suggests it should increase the number of flowers, and the length of the threads.  This may be another of the possible reasons why my saffron usually flowers well each year. 

Saffron from 1 small corm - 3 flowers

Growing saffron at home is cheaper 

Growing your own saffron at home organically is nice, and it is cheaper than buying this spice from the shops.  Given where the majority of saffron in the world is grown, presumably saffron will become even more expensive as time goes on. 

To give an idea of the benefit:cost ratio of growing your own saffron, one company in Victoria currently sells small packets of saffron threads for $3.  These packets contain 6-9 threads, which is meant to be enough saffron for an average dish for 4 people.  

To give an idea of how much this is, the pictures of the little glass jar on this blog post contain 9 threads.  Small saffron corms tend to produce 3 or 4 flowers each, which produce 9-12 threads in their first year.  This means in their first year, each small saffron corm using current retail prices, produces about $3 worth of saffron threads. 

Each year after that the saffron corms tend to grow larger, and produce more flowers.  Individual corms also multiply.  All of this means your initial small investment keeps paying for itself more and more as time goes on.

Organically grown saffron threads

Where to buy saffron corms 

If you are interested in growing your own organic saffron at home, I sell saffron corms over summer when they are dormant.  I can post to most of Australia, but not overseas at this stage.  

I've never tried to post the spice itself, only the live corms for people to grow their own.  I guess I could post saffron spice in little glass jars or something like that.  I may give that a try in the future. 

The Canberra region is pretty perfect for growing saffron, it has hot dry summers and cold winters.  I am sure saffron can also grow well in many other places, but have only tried growing it in the Canberra region.