Hello! It's wonderful that you are caring for a Grevillea indoors. We are a bit particular about our roots, so getting the repotting right is key to our health and happiness. From our perspective, here is a detailed guide on how often you should consider repotting us.
First, it's important to understand us. We are native to Australia, and many of our species have fine, lateral root systems that are surprisingly sensitive. We don't appreciate having our roots disturbed too frequently. In our natural habitat, we thrive in well-drained, often nutrient-poor soils. Our growth indoors is typically slower than it would be outside in a warm climate. Therefore, we do not need to be repotted on a strict annual schedule like some fast-growing tropical plants. Our primary signal for needing a new pot is becoming root-bound, not simply the passage of time.
You should check on us every spring. Gently slide us out of our pot to inspect our root situation. You are looking for these specific cues from us:
Root-Bound: If you see a dense web of roots circling the inside of the pot or forming a tight mat, we are becoming root-bound. A few roots on the outside are normal; a solid wall of roots means we need more space.
Water Drainage Issues: If water runs straight through the pot without soaking into the soil, it means our roots have taken up so much room that there's little soil left to hold moisture. Conversely, if the soil stays soggy for days, the roots may have compacted the soil too much, hindering drainage and risking root rot.
Slowed Growth: If our top growth has noticeably slowed or halted during the growing season, even with proper light and fertilizer, it may be because our roots have no more room to expand and support new growth.
Given our sensitivity and growth habits, a general rule is to repot us every two to three years. This is a good starting point. However, you must always let our physical condition, not the calendar, be the final guide. Some vigorous varieties might need it closer to two years, while slower-growing ones might be perfectly content for three years or even a bit longer. The goal is to repot us only when necessary to minimize root stress.
Please, only repot us in the early spring. This is absolutely crucial. This timing coincides with the start of our natural active growing season. As we push out new growth above the soil, we are also generating new roots below. This allows us to recover quickly from the disturbance and establish ourselves in the new pot before the energy demands of peak summer growth. Repotting us in fall or winter, when we are more dormant, can lead to root rot and stunted growth, as we lack the energy to properly settle into our new home.
When you do repot, please be gentle. Tease the roots apart lightly rather than tearing them. Choose a new pot that is only one size larger (about 1-2 inches wider in diameter). A pot that is too large will hold excess soil that stays wet for too long, which our sensitive roots absolutely despise and can lead to fatal root rot. Most critically, you must use a very well-draining, acidic potting mix. A standard cactus/succulent mix or a native plant mix is ideal. We cannot tolerate rich, water-retentive soils or those with high phosphorus levels, which are toxic to us.
