My plants aren’t growing very well what’s wrong
One thing that can go wrong is the plant food.
No not the nutrient – that is pretty much bullet proof if you are using the Aerogarden nutrients.
It is the water I am talking about.
If that is not good to start with then that can cause major problems.
So what can be wrong with my water
Pure water is neutral – it is not acidic or basic (alkaline).
This means that pure water will not be reactive in itself.
If you vaguely remember your school days – water is made up of H2O.
And in pure water all the H and OH ions are linked together, nothing floating free.
When you add impurities to the water – these react with the H and OH breaking water apart and possibly leaving ‘spare’ ones around.
It is the volume and type of these ‘spares’ that determines the pH or potential Hydrogen of your water.
So how do you get impurities into the water
The water companies will add chemicals to ensure that the water will be suitable for you to drink without getting ill.
Also when the rain falls it soaks through the ground dissolving minerals and fish wellâ€¦they never come out of the water and add to it…
That is one reason the water companies do add cleaning products to the water.
But what is ok for you doesn’t mean it is ok for plants – they can be more sensitive.
You know that if you planted one of every type of plant in your garden not everything would grow.
For some it would be too wet, others too dry – but the soil type would not suit every plant.
They all will grow in the type of soil they evolved in best. Some like acidic conditions and others like less acidic conditions.
Outside certain boundaries they will not be able to feed off the nutrients.
So if your plants are really not doing very well in your aerogarden one of the things you can look at is the water quality you are adding.
How can you tell what quality your water is.
One of the main factors is to actually measure the pH
There are three main ways to measure your waters pH.
Again if you remember your school days in the chemistry lab with vinegar and dipping a little strip of paper into the vinegar and watching the paper change color – that’s litmus paper ( paper soaked in litmus and allowed to dry which shows the number of free H and OH ions )
The color is compared to a chart and the color determines the pH of the solution.
And this can be used on your tap water – to determine whether it is acidic or basic and by how much.
The change of color of the paper is not that accurate and is usually just a guideline.
So yes you can use it … but with varying degrees of accuracy.
So what else is there.
Well…there is a chemical – which when added to a solution will dye it a certain color dependant on the pH of that solution.
You determine the pH by comparing the color of the solution to a chart.
This is more accurate when used properly the right amount of solution to the right amount of chemical.
So again it is work and handling chemicals. They are pretty safe but…..
There is another way which is a bit less work and that is to use an electronic pH meter.
Dipping the glass bulb on the end into the solution gives an almost instant reading of pH.
No mess – no hassle.
The only thing you need to do is to ‘calibrate ‘ the meter every now and then.
You can get sachets of different pH minerals, which when mixed with water ( ideally distilled) will be a certain pH value.
The meter is dipped into this and if the reading is out you can adjust it with a supplied screwdriver.
There are two different levels of pH calibration minerals and using both will give you the most accuracy.
Ok so what is an ideal pH value for plants
Most plants grow with a solution pH of between 5.5 and 6.5 – they like to be on the acidic side of neutral.
The pH scale runs between 0 and 14, with 7 being neutral.
With 0 being like battery acid and 14Â being like lye – either of these are really not good for you or your plants.
Every 1 pH shift is a log10 ( 10 times) shift in the number of free H or OH ions.
So moving from 7 to 6 there are 10x more H ions free , and moving to 5 from 7 there are 100x more.
Adding nutrient to water will normally reduce the pH, so you want to start with water that is slightly higher than the target pH.
So you are looking at neutral or slightly acidic, around the 6 to 7 pH mark.
Ok my water is too low in pH, what do I do.
To adjust the pH of a solution you must remove the number of free H or OH ions.
Carrying this out you add another chemical to the water which will not be harmful to your plants.
This will bond with the free ions and alter the pH of the solution.
On the market are two products pH up and pH down.
And I reckon you can guess which does which.
You only need a drop of this chemical to adjust the pH by a unit ( one drop in a gallon will typically adjust the pH by one unit when close to pH of 6)
So you could dilute the original pH up or down in distilled water if you are after a smaller adjustment, giving you more control.
Add a drop and leave it for 30 mins to finish reacting and test the pH.
So now you know how to check and adjust your waters pH if you find your plants are not growing very well due to the pH being out of the plant optimum range.
Don’t forget to check the solution after you have added the nutrient to the water, leaving it for 30 minutes after mixing.
Now the slightly more techie bit…
PH is the concentration of hydrogen ions (H+) or hydroxide ions (OH-) in a solution.
The number of ions determines the pH of the solution, which will be acidic ( more H+ ions) or basic (more OH- ions) or neutral ( balanced).
If the solution is not a neutral pH it will have an electrical charge in it.
Either positive – being acidic , or negative – being basic.
Plants like a slightly acidic solution for optimum nutrient availability.
Hydroponic plants are grown for optimal growth, so having the optimum pH level would be ideal.
Having your solution at the ideal pH will allow the plants the full range of minerals they need for maximum growth.
The solution within the reservoir will change as the plants takeup the minerals – so changing the solution every two to three weeks is ideal rather than just adjusting the pH or adding more nutrient.
Adding more nutrient can lead to a build up in mineral that the plant doesn’t want or need and can cause poor growth or even terminate the plant.
Adding a bubble stone will help with oxygenating the solution for even better uptake, but it may also adjust the pH as the solution will dissolve carbon dioxide in the solution from the bubbles.
After adding a bubbler – check the pH of the solution and adjust gradually if necessary.
Plants don’t like rapid adjustments in anything.
So lights ideally should come on gently ( as it does at dawn and sundown) and pH changes should be done gradually.
Plants react over a period of 10 minutes to changes in their environment.
So watch out for changes in their appearance.
Unhappy plants droop their leaves or just don’t hold themselves as proud as they did – due to losing water and not replacing it.
Try replacing the solution with distilled water ( or water which is pH between 5.5 and 6.5).
Plants will survive on just water for a few days, before they need the nutrients again (depending on their stage of growth – this will slow down their growth, but better live slower growing plants)
So make sure the water you use is good – between 6 and 7 pH.
And after the nutrient is added ( about 30 mins) check that the pH is in the range 5.5 – 6.5, if not adjust.
If you start using a bubbler in your Aerogarden then check the pH of the solution after a couple of hours and adjust if necessary.
But the main thing is to watch the plants for their reaction- if they look happy and are growing well – carry on.
It is when they ‘go off color’ that you need to diagnose what is wrong, and starting by changing the solution to neutral water may just save them.
Good luck growing
I have been growing plants hydroponically since 2009. For years before that i was reading books and looking at systems and saying ...no way...
But once i had taken the plunge with the tomatoes outside, then there was no stopping me.
I tried out most of the systems and started to refine them, getting the plants to grow more efficiently.
Now I am more interested in indoor hydroponics and the challenges it presents. Being able to control the environment, feeding the correct nutrients and giving the correct length and type of lighting....