I need help diagnosing my plant (Royal Sundae Driver, soil grow).

Ajout cal-mag à ton régime

Was this initially grown with indoor lighting and then put into the sun? If so, could be the cause. Indoor plants need to be slowly adapted to the sun.

The interveinal yellowing mimics magnesium or Iron deficiencies, while the lower leaf death shows nitrogen deficiency. Because the onset was so sudden, it is likely a lockout caused by root stress or a pH imbalance rather than a true lack of nutrients in the soil. Also overwatering starving the roots of O2 is probably why the leaves are drooping. Stop Watering Immediately - Do not add any more water or nutrients until the pot feels physically light when you lift it. Consider pot temp, black outside can get pretty hot. Watch your pH, 6.3-6.5 for soil.

Just by the picture, symptoms are a Nitrogen deficiency , magnesium or iron interveinal chlorosis, and Calcium deficiency rust spots… These symptoms can come from different factors like, proper lack of nutrients, or the EC level of the soil can be too high, overwatering, a poor system, something wrong with the rhizosphere and nutrients not being fixed …. etc, etc …. No one can give an accurate diagnosis without accurate information about the growth cycle.

pH dropped too low, or not enough calmag in the mix? so try to pH your water to 6.3–6.5 and water until you get runoff and add do a light Epsom salt foliar spray for fast relief

Starving for phosphorous.

Check soil temp if it's getting cooked in the sun and temp rising above 74F, causes rapid oxygen depletion, there is far less dissolved oxygen in warm water solutions above 74F, vital to make sure root zones stay cooler.

Hey Rizbiz, sorry to hear your Royal Sundae Driver is throwing a tantrum, but let’s get this sorted out together. Based on your description and the pictures, a sudden decline within 2 to 4 days starting with drooping leaves is almost always a root-zone issue, most likely severe overwatering or poor drainage. When the roots are suffocating from too much water, they can't take up nutrients properly, which perfectly explains the sudden yellowing of lower leaves, the pale new growth, and that classic interveinal chlorosis (yellow tissue with green veins) which looks like a secondary magnesium or iron deficiency caused by a nutrient lockout. First, hold off on watering completely and let that soil dry out until the pot feels lightweight when you lift it. Check the bottom drainage holes to ensure water isn't trapped at the bottom, as sitting in stagnant water will quickly lead to root rot. Once the soil has dried out and the roots can breathe again, you should see the drooping stop. When you do water next time, make sure to check the pH of your water—for a soil grow, you want it strictly between 6.0 and 6.8 to ensure the plant can actually absorb the nutrients already in the soil. Don't rush to dump a ton of extra fertilizers on it right now, as a root lockout will only get worse if you add more salts to the mix. Let her dry out, get the root environment stable, and she should start bouncing back with healthy green growth. Happy Growing Growmie🌱