Fertiliser Tips

  • Fruit Trees that are flowering but not setting fruit. Ray Johnson says a grower gave him some CaB to try out, which is a Calcium Boron mix and where once he got very few Grumichama, his tree is now loaded. Spray it on all your flowering fruit trees.
  • One of our members reports that the use of CaB on early flowering fruit trees has dramatically increased fruit set. This product consists of Calcium sucrose 10.0% & boric acid 1.0% in a liquid form that appears to be rapidly taken up by the trees.
  • We use Cracker Dust - It’s a blue metal and we mix this with fowl dung (about 3:1) but you can change it as there’s no rules but it has a number of advantages. There was an ABC programme on it. There are a lot of minerals in it and its pH is about 9 so it’s nearly as good as putting lime on the ground so you mineralise your ground.  Sheryl What’s the difference between Cracker Dust and Blue Metal?Bob   Fineness. Blue Metal is too course. I’ve found that just by putting it around trees, that the roots come up into it and it’s very inexpensive. You can use it instead of top soil because it’s easier to spread and the grass will green up where you’ve put it – put it on at anytime of the year.   Ref:  Bob Brinsmead - Tropical Fruit World 
  • We were told of the use of Boron and Nitrogen many years ago by Peter Young, a spray of 1gm of Borax, 1 gm of Urea to 1 litre of water.  This had to be sprayed at very early flower bud stage.  The Boron aids the pollination and seed set of the plant.  It also is important for sugar production in the fruit and if overdone makes a great soil steriliser, nothing grows for years.
  • With any crop it’s usually applied at the 1st major flush and there’s usually a window of opportunity from flushing to flowering so during that time, try and push them as much as possible.   Ref:  Ben Waddelow
  • Nitrogen fertiliser will burn away all your organic carbon in the soil so whenever you add nitrogen fertiliser in any form, you need to add a carbon source - either humic or fulvic acid, or compost at the same time – it helps to balance out – it doesn’t draw out nitrogen out of the soil. Nitrogen is a gas and you want to lock it up in the soil. Having a carbon source holds it into the soil. Just having pure ammonium or even pure fish fertiliser within a day or two, the nitrogen will just evaporate. I use foliar fertiliser in the main growing season when there’s new growth - it’s very weak - do it at regular fortnightly intervals. You’re building your brix levels up. You can feed the trees a lot more and by doing that and spraying small droplets over a leaf, it becomes rapidly absorbed into the tree within an hour or two and you can actually see changes in the plant within 4 hours. When they talk about flushing, it either means putting a lot of fertiliser and a lot of water to get that growth happening. If a tree is healthy it will ward off pests and diseases so keep fertilising small amounts which is better than large amounts as the plant can deal with it a lot better. Use stone mulch about 2½” thick white quartz $40.00 per tonne and paramagnetic basalt fines - $100.00 a tonne. Put the basalt fines down first and the quartz on top then compost around the outer ring of rocks – about 3-4 large shovels per tree and you can put it right up to the trunk. As the tree gets bigger, we can extend the ring of stone mulch. I set up a trial over about 20 different trees and I put a whole lot of different materials down as mulch: different rock sizes/particles, different wood mulches, straw, different types of sand then put the water on and let it sit for a day or two then came back and did the finger test and I was very surprised to see the difference – then when it rained, I did another finger test and its amazing how there’s such a big difference between the different types of mulches. The one that held the most amount of moisture was a combination of large 8ml quartz and very fine basalt rock. We expected other mulches to do a lot better but that one was the most effective for us. I’m an Arborist and can get wood mulch but found it broke down after a year and it had to be reapplied so putting down the stone, it didn’t break down. We found with a lot of other mulches in very dry conditions, it won’t allow penetration of a small shower of rain so if you have wood chips, it becomes a barrier so when the water rains on that spot, it will run off elsewhere. Straw mulch will soak up a lot of water but if you do the finger test, under the soil is still very dry. Some of the growth rates we’ve had by pushing the trees hard – we only had sticks when we started – no more than 300mm – and now after 3-4 months, they are up to chest height so we’re hoping that by the end of the season they will be pushing well over head height and fruiting 2-3kgs per tree so it really helps to do your fertigation through your lines and do foliar feeding. We use NTS products.  An Indian scientist I talked to spoke about having a lot of plant vigour – they believe more in pruning so they push their plants with as much fertiliser and water as possible then they’ll go through and prune very heavily so the plant doesn’t lose any vigour but it will shock the tree and it will then fruit very heavily.  Ref: Ben Waddelow
  • For those that do not have access to cheap urea, you can use ammonium sulfate, but use twice more amount per gallon than what Doc Alexis is using (ammonium sulfate is 21% N, about half than that of urea's N). You can also mix together with iron chelates and other soluble micronutrients or seaweed based organic fertilizers and apply foliarly after mildly water stressing the tree (ie, no watering until you see the leaves start to slightly roll), and follow up with normal watering.   Ref: Joe Real