How to Grow Impatiens Seeds
Grow Guide #2358
Binomial name: Impatiens balsamina
Life Cycle: Annual
This 'How to Grow' guide details everything a home gardener needs to know to plant, grow and care for Impatiens (Impatiens balsamina).
When to Sow Impatiens Seeds
Impatiens is a warm season flower. Use the table below to identify the best time of year to sow impatiens seeds in your climate.
Impatiens plants are best grown in full sun or part shade. Choose a location that will receive at least 3 hours of full sun each day.
Impatiens plants need a well drained soil enriched with plenty of organic matter. Prepare soil by weeding it thoroughly, digging it over to loosen it and adding aged animal manure or compost. Keep the area free of weeds until planting. Learn more about preparing soil for planting here.
Impatiens plants can be grown in containers. If possible choose a variety that’s recommended for container growing. Use a good quality potting mix and make sure your container is large enough for mature plants; a minimum of 10 litres is recommended for impatiens. During the growing season, keep in mind that container grown plants may need additional fertiliser to encourage healthy growth.
How to Sow Impatiens Seeds
Impatiens seeds do not require any treatment (eg soaking, stratification) before sowing.
Impatiens seeds grow best when they are raised in trays or other containers and transplanted to the garden once established.
- Fill trays, punnets or jiffy pots with a good quality seed-raising mix, or use soil starter pellets.
- Sow seeds 6mm deep.
- Keep soil moist but never wet or dry.
- Seeds should germinate in around 14-21 days at a soil temperature of 22-26°C.
- Transplant seedlings to the garden once they have their first true leaves and are large enough to handle (usually 5-10cm tall).
- Plant out, spacing plants 30-40cm apart.
Impatiens is a tender crop that’s sensitive to frost. Do not transplant seedlings or sow seeds outside until all danger of frost has passed.
Optional: In cool climates impatiens seeds can be sown indoors 6 weeks before the last expected frost. Grow them in a warm position with plenty of natural light.
How to Grow Impatiens
Impatiens plants need regular watering during the growing season. Do not let soil dry out; keep soil evenly moist but not waterlogged. Water deeply in the early morning or late afternoon. Avoid watering the leaves of plants to avoid fungal diseases. Learn more about watering here.
If soil was well prepared no extra fertiliser should be necessary. In poor soil or to give your plants an extra boost, application of a high-potassium fertiliser or one formulated for flowering plants can be beneficial:
- Apply slow release fertiliser at the recommended rate when transplanting or when seedlings are 5-10cm tall.
- Apply liquid fertiliser at the recommended rate and frequency while plants are fruiting or flowering.
Impatiens plants should flower in approximately 80-95 days.
Deadhead impatiens flowers regularly during the growing season. Using sharp secateurs or snips cut fading or dead flowers off just above a set of leaves. Removing old flowers regularly will encourage plants to produce more flowers. Learn more about deadheading flowering plants here.
Common Problems when Growing Impatiens
Like all plants, impatiens is susceptible to some pests, diseases and other problems. Below is a list of the most common problems gardeners encounter when growing impatiens plants:
- Aphids are small (2-4mm long) sap-sucking insects that congregate on the new shoots or the undersides of leaves. They can cause leaves to wilt or become discoloured, and also excrete honeydew which can attract ants and other insect pests. To manage aphids, remove them by spraying with a garden hose, apply a soap or alcohol spray, or encourage predatory insects to your garden. Read more about aphids here.
- Bacterial leaf spot is a disease that causes irregularly shaped brown spots on all above-ground parts of a plant. The spots at first appear to be wet but become dry and scab-like over time. Leaves and flowers can fall prematurely. Water plants at soil level (not on the leaves), dispose of fallen leaves and fruit and practice crop rotation.
- Grey mould (Botrytis sp.) is a fungal disease that causes flowers to become mouldy and fruit to rot. Spores are transported by wind and can survive in soil or on green waste. The fungus spreads most in cool, damp weather. Prune off affected flowers and fruit, water plants at soil level (not on leaves) and if necessary spray with an appropriate fungicide or homemade spray.
- Damping off is caused by a fungal growth that transfers from the soil to seeds or tender seedlings. Seeds may appear not to germinate, or young plants start to rot when they emerge from the soil and become soft and mushy at the base before dying. Use new potting mix if raising seedlings, do not water foliage and avoid waterlogged soil. Read more about damping off here.
- Downy mildew is a fungal disease that causes yellow to grey-brown patches on leaves, especially the undersides. Water plants at soil level (not on the leaves), remove and destroy affected leaves and do not overcrowd plants to ensure adequate air flow. If problems persist, spray with a homemade milk spray or fungicide.
- Slugs and snails are molluscs that feed on tender leaves and shoots, mostly at night, leaving slimy trails behind them. Control them by removing their hiding places, keeping free range poultry, collecting them by torchlight or by placing traps. Read more about slugs and snails here.