Terracotta planters have a wealthy, orange-red colour that tends to fade or become covered with mineral deposits over time. Although some gardeners like this crusty, Old World look, others prefer a more pristine, well-cared-for appearance. This coating can be somewhat scrubbed away, but stains will remain. By oiling your stained terracotta planter, you can restore your previous planter to its original beauty.
Preparing the Pot
You will need to prepare the pot to be oiled by scrubbing off the areas of the mineral deposits which may be removed. A wire brush will achieve that. You will want to do this slowly and carefully so as not to produce scratches on the surface of the planter.
Oiling the Pot
Rubbing the pot with linseed oil is likely to make the stains invisible. For this process, you may use a gentle terry cloth rag or sponge. You will want to cover the outside of the pot thoroughly with oil. Wipe away excess oil with a dry rag. This process might be repeated since the oil wears off as time passes and new mineral deposits appear.
Commercial sealers are available in nurseries. These sealers are formulated to be used on planters and designed to be nontoxic to plants. Sealers may perform functions such as rejuvenating the appearance of an old pot, protecting exterior pottery from the effects of the sun and reducing the consequences of mineral deposits. You will want to read manufacturer descriptions prior to buying to find the ideal product for your own planter. You should never use a sealer not intended specifically for clay pottery because other sealers might be toxic to plants. These commercial sealers add a sheen to pottery.
You can remove mineral deposits from an empty terracotta pot by splitting the deposits with a mix of 1 part vinegar to 1 part water. A wire brush may be used to scrub away the deposits, after soaking the pot in a sink filled with half vinegar and half water.