Learn About Tulip Bulbs
How to Sow
Planting Fall Bulbs
- Because your bulbs will probably be left where you plant them for several years, good soil preparation is highly desirable. Tulips grow best in full sun in a light, well-drained soil enriched with organic matter. Loose, crumbly soil beneath a bulb encourages good growth and promotes drainage; it is a good idea to prepare the soil at least a few inches deeper than the recommended planting depth. Check the proposed site for standing water after a rainfall. If you must plant where the soil is known to remain wet, raise the soil level by 6-12 inches above the surrounding soil.
- It is a good idea to add fertilizer when you prepare the soil. Be sure to mix the fertilizer into the soil so it does not come into direct contact with the bulbs.
- The general rule for planting is to cover the bulb with soil to 3 times its vertical diameter. In very cold climates, or where the soil is very light and sandy, plant a little deeper. In heavy soils, or in areas with a high water table, plant slightly more shallowly. Plant all bulbs of a kind, when grouped together, at the same depth so they will bloom at the same time and attain the same height.
- For planting clumps of bulbs in beds and borders, dig a hole large enough to hold all the bulbs in one group or drift. Set them upright at the bottom of the hole, tops up (pointed side up), and space properly. Press the bulbs into the soil and cover with the prepared soil to the recommended depth. You can also use a trowel to dig individual holes.
- Tulips should be planted 4-5 inches deep, 3-6 inches apart.
- After planting water thoroughly to settle the soil and to encourage the start of root growth. Sufficient moisture is vital to the health of your bulbs; lacking ample rain, it may be necessary to water new plantings once a week in fall. The roots will continue to grow in fall until the soil freezes.
- Be sure to mark where you planted your bulbs so you know where they are in spring.
- Add 1-3 inches of mulch for winter protection after the ground freezes.
How to Grow
- Flower bulbs also require watering after blooming, while the foliage is ripening. Water weekly if conditions are dry.
- In spring after flowering, do not cut the foliage off; the foliage is part of the perennial growth cycle. Allow it to die back naturally.
- Tulips tend to decline through the years and many gardeners renew plantings annually. They will last longer when they are planted more deeply as long as the soil is well-drained.
- Tulips make great cut flowers, but be careful, they grow once the cut flowers are in water. Add a penny to the water in your vase to help prevent them from growing taller.
Common Pests and Problems
Bacterial Soft Rot: This is mostly an issue with on mature bulbs. Affected scales first appear water-soaked and pale yellow to light brown or bleached gray to white. As the disease progresses, infected tissue becomes soft and sticky with the interior of the bulb breaking-down. A watery, foul-smelling thick liquid can be squeezed from the neck of diseased bulbs. It is spread by water and some insects through wounds on the plant. Burpee Recommends: Discard infected bulbs. Do not plant bulbs with soft spots.
Basal Rot: This fungus causes large dark brown spots on bulbs. White or pink fungal growth will form on the bulbs. Foliage dieds prematurely and flowers are deformed. Burpee Recommends: Do not plant bulbs with fungal spores. Discard any infected bulbs.
Botrytis: This fungus causes a grey mold on flowers, leaves, stems and buds. It thrives in cool wet weather conditions. Burpee Recommends: Remove affected plant parts, avoid watering at night and getting water on the plant when watering. Make sure plants have good air circulation. Contact your Cooperative Extension Service for fungicide recommendations.
Root Rots: A number of pathogens cause root rots. Burpee Recommends: Make sure your soil has excellent drainage. Contact your Cooperative Extension Service for recommendations.
Tulip Fire: This fungus causes the foliage to fail to emerge, be stunted or deformed. Shoots may curl to one side. Dead spots form, surrounded by dark green, then turn white or yellow with small black granules in them. Burpee Recommends: Contact your Cooperative Extension Service for fungicide recommendations.
Virus (Various causes): Flower color may break and flowers may be distorted; foliage may be mottled, have yellow flecks or stripes. Burpee Recommends: Discard infected plants. Be aware if your variety flower color normally has breaks (for example, Rembrandt tulips).
Common Pest and Cultural Problems
Aphids: Greenish, red, black or peach colored sucking insects that can spread disease as they feed on the undersides of leaves. They leave a sticky residue on foliage that attracts ants. Burpee Recommends: Introduce or attract natural predators into your garden such as lady beetles and wasps who feed on aphids. You can also wash them off with a strong spray, or use an insecticidal soap.
Bulb Flies: Adults are hairy flies that resemble small bumble bees. They are blackish to dark green with pale yellow, orange or gray markings. The adults hoover around blooming plants, feeding on pollen and nectar. The larvae are plump, yellow, gray, white or brownish maggots with a short brown or blackish breathing tube at their rear. The larva infests the bulbs, causing yellow foliage and stunted plants with distorted and small leaves. Blooms and small bulbs often die. Maggots often enter bulbs through injuries or cuts into the bulb. Burpee Recommends: Handle bulbs carefully to avoid damage. Remove and destroy infested bulbs and plants as soon as you find them.
Bulb Mites: Shiny creamy white mites range from .5 to 1 mm long and appear in clusters. They infest bulbs in storage and in the field. They damage bulbs by penetrating the outer tissue layer which eventually causes the bulbs to rot. Burpee Recommends: Inspect bulbs before planting and do not plant damaged bulbs. Avoid damaging bulbs when planting or weeding. Remove plant debris after leaves die back.
Slugs: These pests leave large holes in the foliage or eat leaves entirely. They leave a slime trail, feed at night and are mostly a problem in damp weather. Burpee Recommends: Hand pick, at night if possible. You can try attracting the slugs to traps either using cornmeal or beer. For a beer trap, dig a hole in the ground and place a large cup or bowl into the hole; use something that has steep sides so that the slugs can’t crawl back out when they’re finished. Fill the bowl about ¾ of the way full with beer, and let it sit overnight. In the morning, the bowl should be full of drowned slugs that can be dumped out for the birds to eat. For a cornmeal trap, put a tablespoon or two of cornmeal in a jar and put it on its side near the plants. Slugs are attracted to the scent but they cannot digest it and it will kill them. You can also try placing a barrier around your plants of diatomaceous earth or even coffee grounds. They cannot crawl over these.
Spider Mites: These tiny spider-like pests are about the size of a grain of pepper. They may be red, black, brown or yellow. They suck on the plant juices removing chlorophyll and injecting toxins which cause white dots on the foliage. There is often webbing visible on the plant. They cause the foliage to turn yellow and become dry and stippled. They multiply quickly and thrive in dry conditions. Burpee Recommends: Spider mites may be controlled with a forceful spray every other day. Try hot pepper wax or insecticidal soap. Check with your Cooperative Extension Service for miticide recommendations.
Tulip Bulbs FAQs
I live in zone 10, can I plant tulips? No, tulips need about 14 weeks of temperatures below 40 degrees F in order to bloom. You would have to plant them in containers and chill them for 14 weeks, otherwise known as “forcing” them. It will only work one time and you cannot save the bulbs for succeeding years.
Can I grow tulips in containers? Yes, they are fine for containers.
Are tulips deer resistant? Unfortunately they are not. Deer and squirrels love the bulbs and the flowers.
Why do my tulips decline every year while my daffodils get better? Tulip bulbs are not as long lived as daffodils, except for species tulips. To make them last longer, plant them a little deeper than recommended.
I just found tulip bulbs I forgot to plant when I received them! When can I plant them? Tulips should be planted in the fall, about six weeks before your ground freezes. They will grow roots when they are planted, and will go dormant when the ground freezes. If you still have 4-6 weeks of time when the ground is not frozen you can still plant, but otherwise they will not have enough time to grow roots and will not grow well in the spring.