Hi there @Sahana,
Welcome to the Bunnings Workshop community, it is fantastic to have you with us.
It sounds like you're doing a great job monitoring your blueberry plant and taking proactive steps. The symptoms you're describing—new leaves emerging green but turning brown at the tips over time—are often linked to nutrient uptake issues caused by slightly alkaline conditions.
While a pH of 5.9 might seem close to ideal, blueberries are particularly sensitive and typically thrive in more acidic soil, ideally between pH 4.5 and 5.5. At 5.9, essential nutrients like iron and manganese can become less available, which leads to symptoms such as browning tips and overall poor leaf health.
Liquid sulphur is a good start for lowering pH, but it tends to work slowly, especially in cooler weather. If you're looking to acidify the soil more effectively, consider mixing in Manutec Fine Sulphur Granules into the top layer of the soil, following the instructions on the packaging based on the volume of soil in your pot.
You can also use fertilisers designed for acid-loving plants, such as this Scotts Osmocote Roses, Gardenias, Azaleas And Camellias Controlled Release Fertiliser, which will help gently shift the pH and supply appropriate nutrients in a form your blueberry plant can absorb more easily.
Watering can also play a role. Blueberries dislike both soggy and dry conditions, so try to keep the soil consistently moist but free draining. Overwatering or letting the soil dry out completely can contribute to browning tips as well. Make sure your planter has good drainage and avoid letting the pot sit in water.
Since your new leaves are emerging healthy before turning, the main issue appears to be nutrient availability, most likely due to the pH still sitting a little too high. Bringing the pH closer to the optimal range and maintaining steady watering should help your plant recover over time.
Let me know what you think and if you have further questions, please don't hesitate to ask.
Jacob
