The first few weeks can be nerve-wracking if your new to indoor weed growing. While you’ll rarely see every single seedling survive and thrive, you can also waste seeds, time, and money if your conditions aren’t right. Cannabis seed germination isn’t hard, but all seedlings are fragile and can die easily if you don’t take care of them well. The trick is knowing how to diagnosing your seedling issues, and how to fix them.
Healthy Seedlings
A healthy seedling will be green and upright. There will be no yellowing, and it should stand straight up. There should not be much space between the first few leaf nodes, and the plant stem should feel “springy” and relatively firm to the touch. Nothing should be crunchy or mushy. Within a week of germination, you should start to see the first serrated leaves show up, and from there the star shape leaves will emerge quickly.
Underwatering
IF you aren’t watering your cannabis plant enough, your plant will look wilty. The leaves will be limp and the plant may start to lean to one side. If left long enough, the leaves may start to crisp at the edges – once this happens, the seedling may not be salvageable. What differentiates this from other problems is the appearance of the soil: it will be very dry, and may start to pull away from the sides of the pot.
How to Fix It
Start watering the plant more. Water whenever the top inch of soil has dried out. It should never be dry all the way through.
Over-watering
The symptoms of over-watering are unfortunately similar to those of under-watering. The plant is droopy and tipping, and the leaves look limp. However, if left long enough, overwatered plants become mushy, not crispy. The biggest clue that the plant is over-watered is the soil again. Over-watered soil is often soggy or almost muddy.
How to Fix It
Water the plant less, or less often. Plants need oxygen too, and by over-watering you’re suffocating them. Let the whole plant dry out for a few days, then begin to water regularly. Allow the top inch of soil to dry out between waterings.
Starving (Nutrient Problems)
Most nutrient problems result in yellowing leaves. They may also result in red or purple-tinged leaves, spots, and crisping. The tips of leaves often turn brown and curl up. Nutrients that can cause problems include iron, magnesium, calcium, phosphorus, and more.
How to Fix It
Check your growth medium’s pH and adjust if necessary. If it comes in between 5.5 and 6, then do a water flush if you have been fertilizing and reduce your fertilizer use. If you haven’t been fertilizing, start.
Excessive Heat
Plants suffering from excess heat usually show curling leaves that look like canoes. They also start wilting, and often develop strange spots. This usually happens when temperatures remain above 80 degrees Fahrenheit for extended periods of time.
How to Fix It
Lower the temperature in your grow room and move your grow lights further from your plants. Keep roots cool by placing them on some kind of temperature-stable surface – concrete floors work great.
Excessive Light
Plants can get sunburns too. Seedlings are especially vulnerable to light problems. If your leaves look burnt, or if they’re turning yellow or brown and crisping only at the top of the plant, then your seedlings are too close to the light.
On the other hand, if your seedlings grow sideways, have a lot of stem between leaf nodes, or get leggy, then your seedlings aren’t getting enough light.
How to Fix It
Move your light closer or further away from your seedlings, or dim/brighten your light as necessary.
Seedlings are the most delicate stage of life for cannabis plants, but the same problems can happen throughout your grow. If you can get your seedlings to grow successfully, then you have a good chance at keeping your plants healthy through harvest.