When to fertilise
If scarification of annual meadow grass and over-seeding is planned it is better to delay fertilisation until the new ryegrass stand is about 30mm. Applying nutrition earlier to the meadow grass makes it difficult to attain a strong ryegrass sward.
Then there is the matter of selecting a controlled release or readably soluble formulation. Choosing the latter promotes a quick flush whereas a controlled release formulation provides a more steady supply of nutrients over a longer period of three to five months.
A programme of regular fertilisation is fine provided it is well planned and the nutrition is adequate.