Nutrient deficiency in Basil.
Basil (Ocimum basilicum) is one of the most common crops grown in Aquaponics. Basil is a wonderful cash crop and has many uses in the home kitchen or restaurant.
There are two plants that show nutrient deficiencies very readily in your Aquaponics system; number one is basil and number two is tomatoes. We will deal with tomatoes in another newsletter. They are great indicator plants.
Today we will deal with basil and the way it shows nutrient deficiencies in your Aquaponics system. Please take note of the photograph above and you'll see a sample basil plant that is suffering from; primarily, magnesium deficiency (Mg).
As can be seen, as the deficiency in basil develops it will show up firstly in the old leaves and then later in the recently matured new leaves. The deficiency will exhibit as slightly interval chlorosis that is yellowing. The example photograph above shows the deficiency very well and as can be seen, it's easy to detect.
The easiest way for you to ensure there is magnesium in the system is to add it by the systematic use of magnesium sulphate (MgSO₄) which is more commonly known as Epsom Salts. Epsom salts can be easily obtained in supermarkets in small quantities let's say up to a kilo (2lbs) or in larger quantities by going to a produce agency or a farm supply agency. A farm supply agency can also supply you with straight Magnesium (Mg) if that is your preference. If you are growing Basil commercially and need larger quantities it is best to obtain the straight Magnesium (Mg) rather than the Magnesium Sulphate (MgSO₄)
I add Epsom Salts once a month at the rate of one teaspoon of Epsom Salts per grow bed or raft bed in my Aquaponics systems. Epsom Salts or magnesium sulphate is needed in relatively large quantities so you may find if you are growing a lot of basil in your system as a major crop you may need to add double the amount that I have just listed for you. Your basil plants will soon tell you if you're getting it right or not.
It is easy to confuse the nutrient deficiency in Basel thinking it is all Magnesium Sulphate or straight magnesium, but it can also be coupled with iron deficiency so when growing a lot of basil I also add iron (EDDHA iron) at the same rate one teaspoon per bed per month to ensure I've got both covered
Because different nutrient disorders can look very similar if these two protocols I've given you above fail to produce the results you want then the next step will be to send some leaves samples of your basil for laboratory analysis to get an exact diagnosis of the nutrient deficiency your plants are suffering.
Nutrien deficiencies and how to avoid them in your plants are covered in my upcoming Aquaponics Master Class