How to grow tomatoes from seed in a flat with a balcony in moderate climate?
Growing tomatoes from seed is a fun and rewarding experience. Here are some steps to grow tomatoes from seed in a flat with a balcony in a moderate climate:

1. Choose a variety of tomato seeds that are suitable for your climate and growing conditions. Some popular varieties for growing in moderate climates include cherry tomatoes, Roma tomatoes, and beefsteak tomatoes.

1. Fill seed trays or small pots with a good quality potting mix. Make sure the potting mix is well-draining, and avoid using garden soil, as it may contain diseases or pests.

1. Plant the tomato seeds according to the instructions on the seed packet. Usually, this involves sowing the seeds about 1/4 inch deep and spacing them about 1-2 inches apart.

1. Water the seeds thoroughly, but avoid overwatering, as this can lead to fungal growth or rot. Keep the soil moist, but not waterlogged.

1. Place the seed trays or pots in a warm and sunny location. Tomato seeds need plenty of light to germinate, so place them near a window that receives at least 6-8 hours of sunlight per day, or use grow lights if necessary.

1. Once the seedlings emerge, thin them out to one plant per pot or cell. You can also transplant them to larger pots once they outgrow their current containers.

1. Fertilize the seedlings with a balanced, water-soluble fertilizer once they develop their first true leaves.

1. When the weather warms up and there is no longer a risk of frost, you can move the tomato plants outside to your balcony. Choose a sunny and sheltered spot, and water the plants regularly, making sure not to let the soil dry out completely.

1. As the tomato plants grow, you may need to provide support, such as stakes or cages, to help them stay upright.

With these steps, you should be able to successfully grow tomatoes from seed in a flat with a balcony in a moderate climate. Enjoy your fresh, homegrown tomatoes!
Please convert the measurements into CM.