Help

Nutrients are classified as either immobile or mobile depending on if it can be moved around the plant once it’s been fully absorbed. Mobile nutrients are stored in older leaves and can be moved around the plant wherever it’s needed. Immobile nutrients stay close to where they were originally deposited. Deficiencies & excess of mobile nutrients will appear in older growth and leaves first. Where as, deficiencies & excess of immobile nutrients will appear in new growth first usually at the top of the plant. Once you understand the difference and which nutrients are mobile and immobile, it makes it easier to diagnose & fix deficiencies. Whenever you suspect a deficiency, always check your pH first and ensure that it is in the correct range. If it isn’t within the correct range, it won’t be able to absorb some nutrients. So, you could be treating a deficiency, but if the pH is off, it won’t be able to absorb the nutrient still. If your pH is in the correct range, you can now try to figure out what’s going on. NPK the big 3 (& Magnesium) are all mobile nutrients so the plant can take nutrients from old growth and use it for new growth if there is a deficiency which means you would see it all over or at the bottom first. Since growth is mainly affected up top it tells us it's an immobile nutrient. It's not Iron, Zinc, or Manganese. I think it's mainly Calcium due to lack of Boron. Calcium It is crucial for cell integrity and growth. Calcium helps with the flow of nitrogen and sugars throughout the plant. Deficiency usually happens with hydroponics or outdoors in very wet, cool conditions with acidic soil. First sign is distortion and curling of lower leaves. This is followed by irregular yellow-brownish spots with brown borders that grow over time. Finally, root tips will wither and die resulting in a stunted plant with low yields. Boron This element helps with the absorption of calcium. A boron deficiency is pretty rare unless a plant is under-watered or in very dry conditions. It is usually accompanied by other pH or nutrient issues that affect the leaves. Early signs include abnormal or thick growth tips along with brown or yellow spots on new growth. New growth may be twisted, wrinkled, or curl and may die off. The interior of the roots may soften, making it more susceptible to diseases. Foliar spray can help short term until soil is given what it needs. Good luck. Good luck.

Your ph should be 6.0-6.2 in coco. And the canoeing of the leaves is a sign of heat/light stress.