Gladiolus Bulb Care

Proper Planting

• Choose a site in full sun that is protected from high wind. Dig the soil down to a depth of 12 inches, then amend the soil as needed. The ideal soil for planting gladiolus bulbs is sandy, is rich in organic matter and has good drainage. Once the planting area is prepared, go ahead and plant the gladiolus bulbs. The ideal planting time is from early May through mid-June. The planting depth and spacing between bulbs depends on the size of the bulb. Plant large bulbs 6 inches deep and 6 inches apart. Plant medium-sized bulbs 4 to 5 inches deep and 3 to 4 inches apart. Plant small bulbs 3 inches deep and 2 inches apart. Plant cormels or baby corms 1 to 2 inches deep and 1 to 2 inches apart.

Care During Active Growth

• Once the gladiolus bulbs begin to grow, position the plant stakes. Stake plants individually in most cases; the exception is if you are growing long rows of gladiolus in a cutting garden. In that case, you can place stakes every few feet as needed and wrap twine around them to keep all the plants upright. Mulch the area around the bulbs with 3 inches of compost, grass clippings or straw to prevent weeds. The other option is to remove the weeds by hand. Gladiolus need an inch of water per week to thrive, so keep an eye on the amount of rainfall your area receives. Gladiolus are heavy feeders, so fertilize them at planting time with a balanced fertilizer such as 8-8-8. Continue to fertilize them throughout the growing season, according to the label directions on the fertilizer.

Dealing With Thrips

• Thrips are the main pests that attack gladiolus bulbs. Signs of thrip infestation include misshapen or discolored flowers or white streaks on the leaves. Prevent an infestation before planting the corms by soaking them in 160 degree Fahrenheit water for 2 minutes before planting them. As with other crops, it is a good idea to alternate the planting location every year unless you are growing hardy varieties. To deal with thrip infestation on gladiolus bulbs that are already growing, spray plants with Sevin according to the label instructions once the foliage reaches 6 inches tall.

End of Growing Season Care

• The end of the growing season care regimen depends on the type of gladiolus you are growing. For hardy bulbs, the only thing you need to do is cut the foliage off at ground level once it dies back and turns brown. Tropical bulbs are another matter. Dig these after the first frost. Once the corms are out of the ground, rub as much soil off of them as possible. Cut the foliage off directly above the top of the corm and then lay the corms in a single layer in a cool, dark, frost-free place for three weeks so they can cure. When the three weeks is up, remove the shriveled bottom corms from the plump ones that form on top, making sure not to remove the protective covering that has formed on the corms. It is brown and papery. Sort the corms by size and store them in a cool, dark, dry location in a single layer or hung in mesh bags. The ideal storage temperature range is 40 to 45 degrees Fahrenheit.