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Asteraceae
Organic seeds
Sulphur cosmos organic
Cosmos sulphureus
Product code : TOURNE-0037
Sulphur cosmos is an organic, open-pollinated variety that helps gardeners plan a crop suited to Canadian conditions. Its profile works well in flower beds, borders, and bouquets. The sowing, growth, and care information on this page makes it easier to choose a location and monitor the plants throughout the season. Its warm, open flowers suit sunny borders and pollinator gardens. Its warm, open flowers suit sunny borders and pollinator gardens. For best results, choose a suitable location and keep moisture steady while the plants become established. Each packet contains 50 organic, open-pollinated seeds selected for gardens in Eastern Canada. Colour varies naturally.
- Quantity
- 50 seeds
- Exposure
- Full sun
- Life cycle
- Annual
Discover the plant
Common nameSulphur cosmos
FamilyAsteraceae
GenusCosmos
Speciessulphureus
TypeSeeds
Botanical nameCosmos sulphureus
Reproducible seedsYes
Sulphur cosmos organic (Cosmos sulphureus) is an organic, open-pollinated variety selected to offer a clear and accessible growing experience. This page brings together practical information to understand its development, plan the space it needs, and enjoy its qualities in the garden. The format is intended for gardeners who want a methodical approach while keeping enough flexibility to adapt to Canadian growing conditions. Orange and yellow flowers brushed with red create a warm palette while providing resources for pollinators. Orange and yellow flowers brushed with red create a warm palette while providing resources for pollinators. The open flower form remains easy for visiting insects to access.
This variety prefers light suited to the species and season. It grows best in living soil that drains excess water without drying too quickly. Its growth rate depends on available warmth and light. For best results, keep moisture even during germination, then water more deeply once the plants are established. Suitable spacing and good air circulation also support healthy, balanced growth. Orange and yellow flowers brushed with red create a warm palette while providing resources for pollinators. Orange and yellow flowers brushed with red create a warm palette while providing resources for pollinators. Label successive sowings to compare their flowering dates under local conditions.
Sulphur cosmos ( Cosmos sulphureus ) fits easily in flower beds, borders, and seasonal bouquets. Its stated height is 60 to 90 cm. It can be paired with plants that share similar light and watering needs, which makes routine care easier. Monitor flowering regularly and remove faded blooms when that practice suits the variety. Orange and yellow flowers brushed with red create a warm palette while providing resources for pollinators. Orange and yellow flowers brushed with red create a warm palette while providing resources for pollinators. Leave several blooms outdoors for pollinators when gathering stems for bouquets.
Sowing guide
It all startswith a seed.
Sowing depth
6 mm (1/4 in)
Spacing / density
30 to 45 cm (12 to 18 in) between plants
Germination temperature
21 to 24°C (70 to 75°F)
Germination time
7 to 10 days
Sowing period
Sow after the last frost. Frost tender
Propagation
Seed
Growing method
To grow Sulphur cosmos, sow in a light seed-starting mix or directly in the garden when the conditions listed on the packet and this page are met. Keep the seedbed evenly moist without saturating it. Once seedlings emerge, abundant light helps produce compact, balanced plants. The crop prefers light suited to the species and season. Transplant gently when needed to protect the roots. In the garden, spacing should reflect mature size and air circulation. Water at soil level to limit splashing on the foliage. Development remains influenced by temperature and day length. Label each sowing date to compare emergence and bloom duration in your garden. Label each sowing date to compare emergence and bloom duration in your garden. For best results, choose a suitable location and keep moisture steady while the plants become established. This practical approach works well for both first-time gardeners and people with an established vegetable garden. Successive sowings can be considered when the growing season, available space, and crop type make them appropriate. A light mulch can help stabilize soil moisture while reducing competition from unwanted plants. Keep seedlings well lit, harden them off gradually, and label every sowing date for later comparison.
Soil and care
The right care,at the right time.
Care level
Easy
Watering
Water Sulphur cosmos to maintain even moisture during germination, then provide deeper soakings after establishment. The surface may dry slightly between waterings, but the root zone should not dry out completely. Morning watering at soil level reduces losses and helps keep the foliage dry. Maintain even moisture during establishment, then water according to weather. Morning watering helps the foliage dry promptly.
Soil type
Sulphur cosmos prefers loose, fertile, well-drained soil that holds even moisture without remaining waterlogged. Mature compost improves structure and supports soil life. In containers, use a high-quality potting mix instead of dense garden soil. Well-drained, moderately fertile soil encourages balanced growth rather than excessive foliage. Well-drained, moderately fertile soil encourages balanced growth rather than excessive foliage. Avoid low areas where water remains after rain.
Fertilization
Sulphur cosmos benefits from soil amended with mature compost before planting. A light, balanced fertilizer can be added if growth slows or the crop remains in a container for an extended season. Avoid excess nitrogen, which may favour foliage over flowering. Light feeding is enough; excessive nitrogen may favour foliage over flowers. Regular. Assess flowering before applying any additional fertilizer.
Seasonal care
Early in the season, Sulphur cosmos benefits from stable sowing conditions and even moisture until germination. Young plants need sufficient light and protection from abrupt temperature changes. After establishment, watering can become deeper and less superficial, depending on weather and soil texture. A light mulch helps conserve moisture during warm periods. Remove competing weeds without disturbing the roots. Monitoring bloom development makes it possible to remove faded flowers when that practice benefits the variety. Healthy residues can be composted at the end of the season, while plants showing unusual symptoms are removed from the garden. Remove faded blooms or harvest stems to keep the planting tidy and floriferous. Remove faded blooms or harvest stems to keep the planting tidy and floriferous. For best results, choose a suitable location and keep moisture steady while the plants become established. This practical approach works well for both first-time gardeners and people with an established vegetable garden. Successive sowings can be considered when the growing season, available space, and crop type make them appropriate. A light mulch can help stabilize soil moisture while reducing competition from unwanted plants. Harvest or flowering can be monitored regularly so the variety can be enjoyed at its best stage. Results may vary with temperature, light, soil conditions, and the specific microclimate of each garden. Mark selected healthy heads if seed saving is planned at the end of the season.
Container growing
A garden,within reach.
Recommended pot size
10 to 20 L (2.5 to 5 gal) container with good drainage
Sulphur cosmos can be grown in a container when the soil volume matches its development and the pot has effective drainage holes. A loose, high-quality mix enriched with organic matter provides a sound base. Place the container where it receives light suited to the species and season, while keeping it accessible for moisture checks. Potting mix dries faster than garden soil, especially during hot or windy weather. Water thoroughly, then allow all excess water to drain. Light feeding may support continued growth if the mix becomes depleted. The stated height of 60 to 90 cm helps guide the choice of a stable container and suitable location. A stable, well-drained container brings the warm flowers close to a sunny patio. A stable, well-drained container brings the warm flowers close to a sunny patio. For best results, choose a suitable location and keep moisture steady while the plants become established. This practical approach works well for both first-time gardeners and people with an established vegetable garden. Successive sowings can be considered when the growing season, available space, and crop type make them appropriate. Allow enough room for air movement and harvest faded flowers regularly.
Bloom and dimensions
Its place,in your garden.
Mature height
60 to 90 cm
Width / spread
30 to 40 cm
Flower color
Yellow to orange
Foliage color
Green
Foliage type
Herbaceous
Growth rate
Moderate
Growth habit
Upright and floriferous
Bloom period
Flowering in Sulphur cosmos depends on sowing date, warmth, light, and garden conditions. Regular observation makes it easier to follow bud development and, when appropriate for the variety, remove faded blooms to extend seasonal interest. Orange and yellow flowers brushed with red appear through the warm season. Orange and yellow flowers brushed with red appear through the warm season. Timing varies with local warmth.
Days to maturity
70 days
Garden associations
In goodcompany.
Companion plants
Sulphur cosmos can be paired with plants that require comparable light, soil, and watering. Groupings are easier to maintain when each plant keeps enough space and receives sufficient light. Suggested companions are primarily planning tools; undocumented incompatibilities should not be treated as absolute rules. Choose full-sun annuals that share its drainage and watering needs. Choose full-sun annuals that share its drainage and watering needs. For best results, choose a suitable location and keep moisture steady while the plants become established.
Frequently asked questions
Your questions,answered.
How should Sulphur cosmos be sown?
Sow Sulphur cosmos in a light, moist medium at the depth shown on the packet or in the technical information on this page. Keep moisture steady until emergence without saturating the mix. Once seedlings appear, abundant light supports compact growth. Direct sowing is suitable when the soil is warm enough and frost risk has passed for sensitive crops. Indoor sowing can extend the season for plants that need more warmth. After emergence, thinning keeps the best-positioned seedlings and limits competition. Sow after the last frost indoors or directly outside, then repeat every two to four weeks. Sow after the last frost indoors or directly outside, then repeat every two to four weeks.
What exposure is suitable for Sulphur cosmos?
Sulphur cosmos prefers light suited to the species and season. Light quality directly affects vigour, flowering, or production. An open site generally improves air circulation and makes plants easier to monitor. In a very warm garden, light protection during the hottest hours may suit crops that tolerate partial shade, but it does not replace the species’ basic light requirements. Keep the soil loose, well drained, and evenly moist. In containers, orientation and heat reflected from nearby walls may change watering needs quickly. Choose a sunny location where soil drains promptly after rain. Avoid standing water and dense shade. Full sun is preferred.
When does Sulphur cosmos flower?
Flowering time for Sulphur cosmos varies with sowing date, warmth, day length, and exposure. Established plants grown in well-drained soil with suitable light generally form buds more evenly. The usual bloom period remains a guide because local weather can move flowering earlier or later. Frequent observation helps gardeners catch the best stage for bouquets, when the crop is used as a cut flower, or monitor visiting insects. The official page gives no maturity-day figure; weather influences actual timing. The official page gives no maturity-day figure; weather influences actual timing. Sowing date, heat, and sunlight affect when the first flowers open.
Can Sulphur cosmos be grown in a container?
Sulphur cosmos can be grown in a pot when the container provides enough depth and volume for its roots. Drainage holes are essential, along with a quality mix that remains aerated after watering. Place the container where it receives light suited to the species and season, and keep it accessible for moisture checks because pots dry faster than garden soil. Water thoroughly and allow excess moisture to drain completely. Light feeding may be helpful over a long season. Mature size guides the choice of diameter, stability, and any support the plant may require. A stable container with drainage holes is suitable when the plant receives enough sun.
Are Sulphur cosmos seeds organic and open-pollinated?
Yes. Ferme Tourne-Sol presents the seeds for Sulphur cosmos as organic and open-pollinated. They can therefore be saved when the plant completes its cycle and pollination is managed to preserve the variety. Seed saving still requires attention to isolation distance, a suitable plant population, and the correct maturity stage. Some species cross readily with related varieties growing nearby. For a first attempt, label plants clearly, observe flowering, and dry harvested seed completely before storage. Allow several flower heads to dry completely when saving seed. Allow several flower heads to dry completely when saving seed. Store fully dry seed in a labelled envelope away from heat and humidity.
Wildlife and pets
Life,around your plants.
Supporting wildlife
The flowers of Sulphur cosmos may provide resources for visiting insects when nectar or pollen is accessible. Actual activity varies with region, bloom period, weather, and the diversity of neighbouring plantings. Tourne-Sol specifically recommends this flower for pollinator gardens. Activity varies with local weather and surrounding floral diversity.
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