Used to have to buy manure and my gran always followed the horses with a bucket. now they have a very hard job giving it away.I'd recommend going by local horse paddocks to see if they are giving away their manure. Must've saved £20 filling up some old shopping bags for life. Agree with the other posters about not overthinking things, just keep it as simple as you can.
The Gardening Influencers are a bit weird. Just lots of dancing and repetitive content.
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Another thing don't let supermarkets and people on groups make you feel you are late in doing things. Most in groups do it way too early and a lot of their plants die. those who wait later don't lose many and their plants are no smaller than those who went early. Supermarkets and even many nurseries sell forced plants, if ou plant these and a frost hits they will die. My local nursery only sells what can survive. a good nursery wont sell you what will proberbly die if you don't keep them indoors supermarkets and places like B&Q B&M will sell you anything
Many seeds can be planted directly in the ground so until that times passes you are not late