If you sow seeds in pots, when do you plant them outside?

[breatheslowly]

We have sowed seeds about 2 weeks ago and they are coming up. Some now have roots coming out of the bottom of the pot but the seedlings don't look very big or strong yet. The sunflower ones look very long but fragile. How do I know when to plant them outside?

Rule of thumb is after middle of May. You could pot up the sunflowers into larger pots now.
Some seeded flowers i.e. sweat peas, need pinching out of the main stem at 4 " high to make them bushier.

Not had sunflowers.

I plant them up when I get fed up of having them around, tbh. But if I don't run out of patience first, when they have at least 6 true leaves.

I do try to keep them outside, protecting them at night, from the beginning, so they are fairly hardened off from the get go.

What did you sow two weeks ago that have roots coming out of the bottom now? That's incredibly fast growth.

If they are on window ledge, turn them round so each side gets a dose of light, OR cover a piece of cardboard with aluminium foil to make a reflector, and place it so it maximises light all round for the plant.

Middle of May is so risk of frost has gone. Or watch weather forecast for you area, and protect them at night. Yes, put the sunflowers in larger pots, but keep things watered or else they can suffer a 'check' in growth and not recover.

Sounds like your sunflowers are growing too fast. Have you a cooler window you can put them at?