Any ideas why my tomatoes still aren’t flowering?

Five or six hours of direct sun is on the low side for tomatoes, so more light may help if you can manage it. Also check the variety. Some take longer to flower, especially larger or slower-growing types. If the plants look healthy, I’d give them time before making a big change.

Have a look at how the plants are growing. If they’re making lots of lush leaves but no buds, too much nitrogen is one possibility, especially if the fertilizer is nitrogen-heavy. I wouldn’t add more fertilizer without checking the label first. Compost and the initial feed may already be enough for now.

Flowering and fruiting are separate steps. If you’re not seeing flowers at all, variety, plant maturity, and available sun seem more relevant than pollination. If flowers do appear but fall without forming fruit, then heat or uneven moisture could be part of it. Keep the soil evenly moist rather than letting it swing from dry to soggy.