Hello boys and girls!
Today I want to talk about fruit trees in aquaponics.
Yes, it's doable and thee trees seem to love the system, if you have enough nutrients available for these hungry plants.
I wouldn't recommend sticking fruit trees into a new system. It takes time for an AP system to mature and build up a full profile of nutrients, vitamins and minerals.
OK, so, for my system I chose to go with dwarf fruit trees. I did this because of space and because I get to sit three fruit trees in the space of one larger tree.
Step 1: What Is a Dutch Bucket and How to Make One.
Sketch shows a complete Dutch bucket.
A Dutch bucket is a constant flow system that stores just 5cm of water at the bottom of the bucket at any time.. As water flows in through the opening at the top of the bucket, it drops through the plant roots then fills the 5cm section at the bottom. once this area is full, the water slowly overflows down the drain pipe. This constant flow means that the water remains oxygenated and prevents root rot. It also allows the plant to access any water or food it wants. It also means that the water that leaves the bucket has less nutrients in it and is cleaner when it flows back into the sump tank.
Cut your bucket to it's desired size. I chose half the size of my 220L drum. So my final bucket leaves a lot of space for tree growth.
Once cut and smoothed, I cut the hole about 5cm from the bottom. I chose to use 1.5" PVC waste pipe. Along with it's corresponding uniseal. The uniseal needed a +-57mm hole.
To make the hole, start drilling with the drill spinning forward until the drill bit section of the hole saw is through the plastic. Now, when the hole saw teeth are ready to cut, switch the drill into reverse.. This will prevent the teeth from gripping and it will make a smoother hole which allows the uniseal to make a better seal.
Now, you have a hole in the side of the bucket, the bottom of said hole is approximately 5cm from the bottom.
Insert your uniseal and then take your pipe and drill a series of 8-10mm holes in the section that will be inside the bottom of the bucket. Make sure to measure so that the holes end before the pipe goes through the uniseal as this will allow water to leak out of the system.
These holes are there to allow the water to overflow back into the system without allowing your stones to leave the bucket.
Step 2: Build a Strong Frame to Hold and Hide Your Buckets.
So, you have your Dutch bucket/s and you need a stand for them to hold them at a height above the sump tank. This allows the water that leaves the buckets to return to the system using gravity.
This is where I made a small mistake. I built the frame when I planned just two buckets. Later I chose to add a third. The weight of this forced me to add extra legs along the bottom to spread the weight. If you plan on holding two or more buckets, add more legs, one leg every 60cm is best. I would also recommend using 50mm x 100mm rather than 50mm x 75mm timber. This will add strength to the system.
OK so build your frame.
Next, screw down timber to act as a base on which the buckets will stand.
Now, I used decking timber to surround the frame and make it look nice. You can do your own thing. Just make sure that your stand is strong enough because 110L of stones weighs about 100Kg. If you go with three buckets like I did then you need the stand to hold 300Kg plus any water.
I had a little helper to make this job more difficult. He meant well but daddy's way is boring. He decided that there are more exciting ways to use one's time in the workshop.
Step 3: Adding Return Drainage to the System.
Next I attached a drain pipe to the base. It has one pipe for each bucket.
The 1.5" pipe that acts as a drain in the Dutch bucket, connects to an elbow. The elbow turns downward and connects to the drain. This drain then returns to the sump tank.
Step 4: Bringing Water From Sump to Top of Bucket.
So, we have the buckets and the water return pipework. Now we need the water supply for the buckets.
For this I used a 1" PVC pressure pipe that supplied the water for all three buckets.
Along the 1" pipe I placed 1" T pieces. Each T was reduced to 1/2" that added water to each individual bucket.
I made sure that each 1/2" supply pipe was fitted with a Ball valve. this allows me to adjust water flow to each bucket or turn any off, as needed.
As you can see, the supply pipe does not spray down from above. It sprays the water under the stones. I did this because, when you wet the top of the stones they grow nasty algae. By depositing the water directly to the base of the plant, you limit algae and make sure that each plant is provided for.
If you choose to add two plants per bucket, you just add a second down pipe to the base of the second plant.
As you can see in the picture, I painted one of the Dutch buckets. it was a test to see if it looked better and it did. So I plan to paint the rest this winter.
I know I have mentioned A1 Pond Paint (Made by Antel) before but I will again, simply because it is the best paint for any job where you need to seal and waterproof something that will hold fish or animals.
It covers well and a little goes a very long way.
Step 5: Choosing the Right Stones and Filling Buckets.
Now that all of the plumbing is done and the system is ready to supply water, you need to run the water for a few hours to make sure that there are no leaks in the supply or return pipe work. If that all checks out, you need stones.
If you are running a hydroponic system you don't have to be as strict with your choice of stones but if you follow the guidance you cannot go wrong.
For an aquaponic system, you need to make sure that you are using stones without contaminants. Most importantly, you need to make sure that your stones do not contain limestone. You can check this by placing a hand full of your proposed stones into a cup and covering them with spirit vinigar. If they do not bubble then they are OK, so far.
Next, take another hand full, (NOT the same ones that you used for the vinegar test.) Rince With RO Water then Add them to a separate cup. Now you need to take some of your reverse osmosis water and check it's PH. Once you know the water's starting PH, add it to the cup with the stones. Stir well and leave overnight.
The next day, test the PH of the water in the cup. If it has changed a lot then you cannot use the stones but if it stayed the same then you can use the stones.
Before adding them to your system, rinse the stones well with tap water. This will remove any Fine silt from the stones and in turn, prevent future issues.
Now add your stones to the Dutch bucket. once you have covered the drainage pipe, put your fruit tree into the bucket. Next, cover the roots of the tree with the rest of the stones and put the water supply pipe in place, it's end approximately 5cm below the surface of the stones. ..
Your fruit trees are now in place and in time they will come to life. Don't be surprised if your trees do not produce fruit on their first year. They may be too young or they may still be growing their roots to absorb the plentiful nutrients.
Something I've noticed is that plants' roots grow differently in AP systems. They appear much finer. I assume it's because they don't need thick roots to find food and water. They just need lots of fine roots to collect as much as possible. This may mean that a tree taken out of an AP system and planted in your soil garden would need time to adapt.
Step 6: Conclusion.
Now that you have completed the project, be patient and in time it will look the part.
You can see the difference between the pictures above. That took just 4 weeks as it was spring when I finished the buckets.
I now have three Dutch buckets.
They each have two plants.
Bucket 1. Dwarf Duo Pear tree and Kiwi vine.
Bucket 2. Dwarf Duo Apple tree and a grape vine.
Bucket 3. Dwarf Duo Apple tree and cherry tomato plant..
A duo tree has been grafted with a second strain of tree. So, on one dwarf tree I will grow two types of apple. Mine grow Bramley and Granny Smith apples on each individual tree..
OK, that's all I have to tell you.
I hope you enjoy this project and remember, I am always happy to answer any questions. Just ask and I will do my best to answer ASAP.