Here's a photo of a winter veggie garden in Vancouver. I'm aware that Vancouver grows winter veggies for the homeless which is a good idea. This photo may give you a few ideas for winter gardening. Welcome to a world made for gardening fanatics. Cheers Here is a link that might be useful: Winter veggies in Vancouver

I would wait to replace the mix until after the flowering is over. Your plant right now is putting all its energy into the reproductive cycle. It might help at this time if you can install a wick up through the drainage hole to improve the drainage now. You would probably have to lay the half barrel over on its side to insert a wick of about a quarter inch diameter up about a foot into the mix. This will only work if the container is elevated some off the ground so the wick will extend a few inches out of the drain. Read the container gardening forum for more information on wicking. When you are ready to repot check with the landscape supply companies where you live. I have a choice of 10 different mixes, available in any quantity, most bark based in Santa Rosa. Al

I applaud you for the effort you have gone to, to get your grevillea growing in a pot. When you water the pot, perhaps you could try immersing it in a bucket of water, until all the air bubbles stop coming out of the pot. This really is the best way to water pots. Sometimes potting mixes become "hydrophobic" which means they repel water, and it is difficult to water pots from above when this is the case. Perhaps you could try buying a smaller Grevillea banksii, the one in the picture is large and does look like it should be in a bigger pot. A smaller plant might be easier to handle and would have a greater chance of getting used to its situation, early on. If you buy a plant that is reasonably advanced it has become used to its place in the nursery. Then you take it home and plonk it on your balcony and it could go into shock. A word about the cow manure, make sure it is well rotted. You sound like you are interested in plants, perhaps you could do some research into your "local species", I am sure there are horticulturists in Brazil who must be interested in preserving the local plants. Sounds fascinating. Drainage is important too, so let the pot drain when you have done the immersion in the bucket. It is equally important to make sure the pot does not have too much watering. So make sure there are dry periods between watering. You could stick your finger into the potting mix to get an idea as to how wet the mix is. I have seen this tree growing near me and it is huge. Here is a link that might be useful: Plants of Cerrado region.

Yeah not looking too good Pal, Aussie natives, and I reckon even South Africans, (leucadendrons) can be difficult outside of their native habitat. Having said that both of those like similar conditions; neutral to slightly acidic soil, excellent drainage, and they hate root disturbance. In fact you can easily over care for them - both are very tolerant of dry conditions. Many also are not happy in humid conditions. Lime, by the way, will yellow the leaves and eventually kill them so I reckon the first thing Id do is check the ph. in the soil. Oh, and if you feed them use only fertilisers suitable for Aussie natives, and use it sparingly. Other than that good luck with 'em B.