The location on the plant matters too! They aren’t just using upper and lower leaves at random. Some nutrients are mobile. That means the plant can move then around inside the plant. Mobile nutrient deficiencies tend to manifest in the lower leaves, because the plant will redirect them from old growth to new growth. Some nutrients are immobile. Once a plant takes them up and uses them, putting them in place, thats where they stay. Immobile nutrient deficiencies tend to manifest in the new growth, because the plants cant use the nutrients locked up in old growth. Also, depending on the plant, over watering can cause root issues which can manifest in all kinds of symptoms.

The location on the plant matters too! They aren’t just using upper and lower leaves at random.

Some nutrients are mobile. That means the plant can move then around inside the plant. Mobile nutrient deficiencies tend to manifest in the lower leaves, because the plant will redirect them from old growth to new growth.

Some nutrients are immobile. Once a plant takes them up and uses them, putting them in place, thats where they stay. Immobile nutrient deficiencies tend to manifest in the new growth, because the plants cant use the nutrients locked up in old growth.

Also, depending on the plant, over watering can cause root issues which can manifest in all kinds of symptoms.