Some Oxalis varieties, such as 'Iron Cross', are fully hardy and can be planted directly outside without frost protection. Others, such as triangularis and regnellii are frost tender, and should be started under cover in spring, before moving outside once all risk of frost has passed in your area.
— Oxalis varieties are fresh at the time they are supplied. Whilst they can be planted in spring or autumn, they should be planted in the season that they were supplied to you, whilst still fresh.
— The bulbs are naturally small. Plant them into pots with multipurpose compost between March and May and grow tender varieties like triangularis and regnelli on indoors. They can be moved outside from May onwards, or kept indoors to grow as a houseplant. Alternatively, you can plant the bulbs straight outside in May.
— Hardy varieties like Oxalis deppei 'Iron Cross' can be planted directly outside in spring.
— Plant the bulbs 5-10cm deep into patio containers or temporary pots (if intended to plant out later). Any shoots which have already emerged should be kept intact and facing upwards. If they are long enough, they will be a little exposed after planting. There may be no shoots, or in cases where they are shoots but they are not long enough, they should be submerged.
— When planting outdoors, choose a sheltered position in full sun or partial shade with free-draining soil. Space the plants around 10-15cm apart from each other in borders or containers.
— Water-in after planting and continue to water regularly once you see the leaves appear or if the soil becomes very dry. Don't allow the bulbs to sit in wet, cold conditions for long periods of time.
— Move frost-tender varieties like Oxalis triangularis and Oxalis regnellii to a frost-free location for winter, such as a cool greenhouse, or indoors. They are naturally deciduous, so if growing them as a houseplant stop watering when the plant begins to die back in autumn, and begin watering again in spring.