They need wind for strength. Plants grown outside are faced with windy days which in turn create a stronger thicker stem.The plants are overcrowded. Although growing densely is great for indoor microgreens, the plants become stressed and compete for light and resources creating leggy plants.If you have grow lights it’s better to have them a few inches above the plants and raise them as the plant grows. The light source is too far away and the plant is reaching for light.This is really easy to happen for the following reasons: Leggy seedlings are when the plant is long and thin and not growing straight up. Over watering is the most common seedling mistake which then creates other problems, from root rot, mold to gnats and damping off. This is a problem both inside and outside. The most common reason why seeds rot is overwatering. If the soil in your garden beds looks disturbed after heavy rainfalls that might be cause of seeds not germinating. Washed away. Seeds sown outside right before heavy rains might have been washed away.Seeds like sprouted peas or corn are often taken by birds or squirrels. Someone stole the seeds. If you sowed your seeds outside, it’s possible that a critter stole the seeds.Tiny seeds like carrots or lettuce only barely need to be covered with dirt. Be sure to carefully read the seed packets and make sure you’re sowing at the right depth. This is a very common mistake, people sow seeds too deeply. The seeds were sown too deeply into the soil.This depends on how they were stored and the type of plant.

Just because they are old, doesn’t mean they won’t sprout, however in general older seeds have lower germination rates over time, which means if you sowed 30 seeds, maybe only 10 germinated if they are older than a few years. You can germinate old seeds, but often they have less plant vigor.