Hello Jane thanks for your inquiry, it's advisable that newly planted seedlings be supplied with sufficient amount of Macro nutrients specifically Phosphorus (P) to enhance root development which ultimately contribute to vigorous growth having mentioned this for industrial fertilizers a period not greater than 7-10 days is a appropriate this is when new root hairs start forming and usually the young crop will shown development of new shoots(leaves). For farm yard manure or compost manure they release nutrients slowly to be made available to crops, for maximum benefit you ought to have incorporated then in soil during the land preparation process for your kales and cabbages to utilize it properly but still ensure it's aged properly/ well decomposed and incorporate it as immediate as you read the feed back.I have just transplanted kale salad, cabbages and spinach without using either fertilizer or manure. My intention is to apply at a later date, but I don't know how long I should wait before applying. Someone advice me.
Morning Jane? If your crops are older than periods as I described before then make application right away.So at what stage should I app6now that I didn't?
Welcome all the the time @ eLengoOk. And thanks for the advice.