It’s so nice when things work as they’re supposed to!
The grafting in Carr’s Organic Fruit Tree Nursery finished a few weeks ago, and now we can see whether it worked or not. Excitingly, most of them did!
This is always a time of some trepidation, as we’re faced with irrefutable evidence of the quality of our grafting technique.
While our mentor (and Katie’s dad) Merv is always there teaching and advising, he’s handed over the actual grafting to us – so there’s no hiding any more. The success or failure is ours to own!
So it’s incredibly gratifying to see that our success rate this year was actually pretty good, and definitely better than last year!
Spring is also when we get confirmation on whether last summer’s budding was successful. We always check whether the buds appear to have “taken” before we cut the rootstock back to the bud in late winter, but you’re never really sure until you see this:
It’s also a good time to check whether the establishment pruning you did in on your young trees in winter has produced the desired effect.
The point of making a heading cut (as we describe in Pruning Young Fruit Trees) is to create new branches, in the desired location in the tree.
And here’s an ideal result, where the three shoots directly below the cut have all started growing, creating three new branches in this young cherry tree exactly where we want them.
In organic growing we don’t use chemicals that damage the produce, people or the environment, but that doesn’t mean we don’t spray!
All deciduous fruit trees are prone to fungal diseases, some more than others, and if they’re not properly prevented or controlled in spring, they can be devastating.
We don’t have room here to go into a lot of detail about individual diseases, so we’ll focus instead on the basic principles of fungal disease prevention.
Each fungal disease has trigger points that stimulate an outbreak of disease – a unique combination of temperature, the number of hours the tree has been wet, and the amount of spores present, amongst other things (we go into more detail about individual diseases in the Keep Your Fruit Trees Free from Diseaseshort course).
Regardless of the disease we’re trying to prevent, the aim is to keep your trees protected at all times while they’re flowering with what we call a “cover spray”
This means we’re aiming to have the trees covered with something that will prevent the fungal spores from causing a disease outbreak.
The regime differs a bit depending on what disease is posing a risk, but the same principles apply. Put an organic fungicide spray on, and then if you’ve had a lot of rain (more than about 25mm, or consistent rain for days on end) assume it’s been washed off and replace it.
An effective spray available to organic growers is copper, normally mixed with builders lime (when it’s called a ‘Bordeaux’ mix).
However as always, it’s important to consider the pros and cons. Copper is such an effective fungicide that it can have quite a detrimental effect on the soil because it kills the soil fungi, which are vital to the health of the soil and your trees. So, our compromise is that we only ever use copper once or twice a year.
In an ideal world, the tree’s natural defense system (including naturally occurring microbes on the leaves) would prevent a disease outbreak, but for many growers, their trees still need some protection.
Another spray we can use in organic orchards and gardens is sulphur, which is much ‘softer’ and less damaging to the soil, but also less effective at preventing outbreaks of disease. It’s likely to get washed off by rain more easily though, so it may need replacing more often.
Whey is another spray that is often recommended for organic fruit trees, but we’ve not used it ourselves and it’s hard to get any good data about its effectiveness. If you plan to use it please do some ‘citizen science’ and keep good records (including photos) of what you use, when you use it, and your results – and then send them in to us, we’d love to see them and share any new-found knowledge.
On a side note, one of the orchards in the Australian Network of Organic Orchards reported back on a trial he did with potassium silicate and potassium bicarbonate to prevent Black spot fungal disease in apples – and it was almost a total failure! So be warned, if you’re trialing an unproven product set up a small controlled experiment rather than risking your whole crop.
We’ve been getting lots of good pruning questions lately, so we thought we’d share some with you today.
1. Is it too late to prune now? No, is the short answer.
Generally we prune most fruit trees (apples, pears, peaches, nectarines and plums) in winter while the trees are dormant, but as with all aspects of pruning – there’s no ‘right’ or ‘wrong’ thing to do, just cuts and consequences.
So, what are the likely consequences of pruning in late winter/early spring?
Pruning in winter encourages a strong growth response in the trees, and the later you prune the less the tree is likely to grow in response. If your trees have already broken dormancy when you prune them, you’ll be wasting some of the energy they will have already put into growth. But that may be better than leaving them completely un-pruned.
2. What’s the difference between a heading cut, and a thinning cut? At the end of every branch or lateral (smaller side-branch) is an ‘apical’ or ‘terminal’ bud, and it releases a hormone that suppresses the growth of the buds below it. Any time you make a cut that removes the apical bud it’s called a ‘heading’ cut, and therefore the effect of a heading cut is to create branching. This is a very stimulating type of cut, as usually the 2 or 3 buds immediately below the cut will start to grow.
On the other hand, if you make a pruning cut back to a lateral, but leave the lateral intact – i.e. leave its apical bud in place, that’s called a ‘thinning’ cut.
This is a less stimulating type of cut, and is a good way to remove some wood from the tree without creating branching.
3. Should you remove all growth going into the middle of the tree? Large branches that are going into the middle of the tree, especially high up in the tree, can create shading over the lower branches, and should usually be removed.
If there are a lot of large branches to remove, it’s a good idea to do it over a few years rather than all at once, because trees will try to replace all the wood you remove from them, and the aim is to keep the trees in balance between producing wood, and producing fruit, therefore aim to remove as little wood as needed each year, to create the shape you want.
However, small branches (or laterals) that are going into the middle of the tree usually do not need removing, and in fact can be very useful fruit-bearing wood.
In fact, removing all laterals that go into the middle of the tree is one of those “rules” that can end up doing quite a bit of damage to your tree, as it’s easy to create long bare patches on your limbs by removing these laterals, particularly low down in the tree where it’s easy to reach them. Those bare patches become wasted real estate, as you’ve effectively removed all the fruit growing wood – it’s one of the rookie mistakes we help you avoid in our Pruning Mature Fruit Trees short course.