The aerogarden series of units come prepacked with seed pod kits and their own brand of plant food. Once this has gone you have several alternatives, in this article i discuss what your options are and what alternatives are out there…
What’s in Aerogarden liquid plant food: Aerogarden’s Liquid plant food is a proprietary mix of mineral salts and a pH buffer. The main nutrients ( the N-P-K) ratio is 4-3-6. It has been designed to help your plants grow well over the whole of their life.
After germination plants need food, whether this comes from soil or other means they don’t care – they just need food ( and water and light and air). Within hydroponics you replace the soil with liquid nutrients made up of mineral salts. The different minerals help them in the various stages of growth. As the Aerogarden plant food supplied only lasts one season, lets find out what’s in it and what the alternatives are….
What’s in aerogarden liquid Plant Food
As i said above plants need food- soil or mineral salts – to them it doesn’t matter .
All they want to do is grow.
Soil, or compost, will supply them with most, if not all, of their requirements – but unless you get samples tested you don’t know what is there or missing…
But with hydroponic nutrients, they have been designed to give them all of what they need.
The Aerogarden plant food contains a mix of mineral salts including Potassium nitrate, Calcium nitrate, Mono potassium phosphate, Ammonium nitrate and Magnesium sulphate.
All of these will be broken down by the plant into the various nutrients of nitrogen, Phosphorus, Potassium, calcium, magnesium and there will be trace elements as well.
Like iron, zinc, sulphur, manganese, boron, chlorine, copper, molybdenum, and silicon.
All of these are needed in various strengths throughout the plants life and making them available in the required levels allows the plant to grow at it’s own natural rate – dependant on other external elements.
It is unusual the way they have been able to make a single bottle to cover all the nutrients ( the main thing i would say is to give it a good stir before using it – yep a stir rather than a shake, get a bamboo barbecue skewer to get right down to the bottom , where the solids are to get them moving )
This way the plant will definitely get all the nutrients it needs.
This nutrient mix is good for all stages of growth, you may need to cut back at the start after germination – or with cuttings, but it is good for vegetation, flowering and fruiting.
The 3oz bottles are good for up to 12 feedings at 8ml every two weeks.
There is a larger volume of 1l which will be good for 125 feedings and at a two week continuous rate is good for two and a half years…
They do have a shelf life so if you are not going to continuously grow then it might be worth going with a smaller quantity…
or look at an alternative.
What nutrients do plants need
If you look on packets of fertilizer you normally see three numbers.
These are the three main ones that they need to grow.
The N-P-K ratio within the fertilizer.
N is the nitrogen – needed for good leaf and stem growth.
P is the Phosphorus – needed for germination, photosynthesis and flowering.
K is the Potassium – helps the plants immune system, root growth and food transportation.
These are classified as the macro nutrients – you need loads of them volume wise.
Then you move onto the micronutrients – you need less, but they are still very important.
Magnesium – found in every molecule of chlorophyll and helps absorb some of the other nutrients.
Calcium – they need almost as much of this as the macronutrients and some add it to that class. It is needed for cell manufacture and plant growth.
Sulphur – it is a base building block for plants hormones, proteins and vitamins, it helps with respiration of te plant.
Zinc – helps with chlorophyll formation
Manganese – helps with photosynthesis
Iron – helps with photosynthesis, helps with absorbtion of other utrients.
Boron – helps the plant mature and with its respiration.
Chlorine- helps with root and foliage development.
Copper – needed in very small amount to help with food generation.
Molybdenum – helps increase plants growth and health, important for helping absorb nitrogen and potassium.
Silicon – helps strengthen cell walls and improve the immune system.
From the above list that the plants need , if you looked up a book for humans you will find many of the same requirements.
This is one of the reasons eating plants is good for us – we get these nutrients from the plants…..
But now knowing what the plants need we can start to look at what alternatives are available to use in the Aerogarden.
What alternatives are there
One thing i have found in my investigation into this is that the two and three part solutions are there for a reason.
If you mix calcium and sulphur you get calcium sulphate or gypsum (plaster).
This is the reason you may see the one part nutrient solutions being cloudy as this has solidified out and cannot be accessed by the plants.
So unless they have sorted out a way of not allowing these two vital nutrients to mix i would rather have the hassle of using a two or three part nutrient solution.
I was introduced to the canna range – canna vega and canna flora.
These are two part mixes where the calcium and sulphur is kept separate.
You add the same quantity of each bottle – i use a 2.5ml syringe as it is 2ml per liter, and the Aerogardens i have take 3l, so a dose of 6ml of each bottle – mixing into the water well before adding the other.
The macronutrient are rated at 4-3-6 in the aerogarden
nutrient plant food and with the canna vega it is a combination of part A 5-0-3 and part B 0-3-5 – or combined 5-3-8 close to what the aerogarden mix is.
Others have gone for the dry mix of the General Hydroponics Maxigro with its levels of 10-5-14 ( which if you divide by 2 is 5-2.5-7) again close to the aerogarden nutrient, but they like round numbers.
Is there anything else you need to look for in the nutrient before it is a good candidate for use in the aerogarden
What to look for in a nutrient
As we have found above plants need a lot of nutrients.
But the concentration of these is not the only thing that is needed – you need to take into account the acidity of the mix or the pH level.
Pure water is neutral, lemon juice is acidic and chlorine bleach is base ( or alkaline).
Plants like to have their food slightly acidic and with the scale of pH running from 0 to 4 with 7 being neutral, most plants will take up their nutrients between pH values of 5.5 and 6.5.
So if the pH of the nutrient is changing, and in a small reservoir it will change a lot, then some of the nutrients may not be available to your plants.
But there is something called a pH buffer which resists changes in pH.
And this is very good for small reservoirs.
So this definitely needs to be included within your hydroponic nutrients.
If you want to know more about this then this post on water quaity will help.
What’s the cost difference
So in a 3oz bottle of aerogarden nutrients you can get 12 feeds
A 1 liter bottle is 125 feeds
The two 1liter bottles of canna you can get 167 feeds
And the general hydroponics maxigro you can make 200 feeds.
So if you look up the price of all three then you can work out whether you want to use the original or go with another liquid feed, which is a two part or mix and dissolve crystals.
So what do I do
As i have said above i was introduced to the canna range – using it for dwc for tomatoes outside – and after using up the aerogarden nutrients received with the units i transferred over to this and have not really looked back.
I have not carried out thorough checks with a pH meter , but have occasionally checked it and found it to be within limits.
I don’t change my nutrients when the change nute light comes on, but may go two cycles before replacing it- does it harm the plants.
Well as mine are well established chili plants and they increase the heat for a little stress then i know it does not do them any harm.
If i was working with young plants then i would stick to the replacement every two weeks. This way they get the best levels of nutrient.
What do i do with the left over nutrient – occasionally give it to my other houseplants who are not as luck as the ones in the aerogarden.
You do need to watch out for salt build up and if you see a white deposit then flush the plant through with clean water to reduce the salt buildup.
Would i try the general Hydroponics nutrients – yes if they were freely available in the UK, but with postage they work out more expensive than the canna.