April can be a very unpredictable month weatherwise. Some days warm some days cool.
TIP: Ensure you keep an eye on the weather forecast so that you don’t go overwatering your plants when a cool spell is expected.
If you have been using a high nitrogen feed this needs to be stopped now.
TIP: Go over to using a balanced feed from now on. TIP: The strength of feed for show plants should be governed by how often you need to water, for example 1 week or longer full strength, twice a week around half strength, every other day around quarter strength. Realistically though you are unlikely to need to water every other day unless the weather is very warm.
TIP: This month is also the time to get your greenhouse shading on. The sun is getting stronger by the day now and if we had a warm spell of weather the leaves of some plants could scorch. There a number of brands of paint / spray-on white wash for greenhouses. Some of the newer ones even go clear when it rains. Always follow manufacturers instructions.