How to Divide Bulb Offsets
By The National Gardening Association, Bob Beckstrom, Karan Davis Cutler, Kathleen Fisher, Phillip Giroux, Judy Glattstein, Mike MacCaskey, Bill Marken, Charlie Nardozzi, Sally Roth, Marcia Tatroe, Lance Walheim, and Ann Whitman from Gardening All-in-One For Dummies
Many flowering bulbs produce offsets (daughter bulbs) as a way to make more of themselves. Bulb offsets are an easy, inexpensive way to get more flowers for your garden. Daffodils are an example of bulbs that are excellent at multiplying themselves.
The bulb you originally planted makes some offsets at the edge of the basal plate, and the original mother bulb nourishes them as they grow. In due time (and it only takes a couple of years), the daughter bulbs become large enough to flower themselves. Then they start making daughter bulbs of their own. Eventually, the clump of bulbs becomes so crowded that heavy competition for nutrients can cause flowering to decline. At that point — or even sooner — you need to step in with a shovel and separate the bulbs.

Divide a clump of bulbs by separating the offsets and planting them.
Offsets are actively growing plants and thus need different handling than do dormant bulbs in autumn. Dig and divide a clump at a time to reduce the risk of roots drying out, and then follow these steps:
Prepare the new soil if some bulbs are going into a different location.
Add organic matter — compost, leaf mold, or dry manure — and granular fertilizer. Have the same materials available to rejuvenate the original location.
Dig the bulbs one clump at a time.
One clump of overcrowded daffodils may produce as much as 50 bulbs! Dig only what you can handle at one go.
Cover the bulbs with wet burlap or wet newspaper as you work.
Locating bulbs that still have leaves attached is much easier than searching for leafless bulbs lurking incognito beneath the soil.
Take a group and gently twist and rock the bulbs back and forth until they separate.
The best time to separate bulbs is after the flower blooms have faded, but while the leaves are still green and growing vigorously.
Replant as many as you want at the appropriate depth.
You can choose to replant each and every division, down to the smallest, or only those big enough to flower in a year.
Mulch and water.
Watering is important because you want the roots to re-establish quickly and nourish the leaves, enabling the bulbs to store more food and flower sooner.
Unlike daffodils that make offsets, gladiolas make little cormels, or baby corms. After you dig at the end of the growing season and find these cormels, store them separately from the large, flowering-size corms. Before replanting the next spring, soak the cormels in lukewarm water for a couple of hours — they have a very hard tunic, and can root more easily if the tunic is first softened by soaking. The new gladiolas will probably flower the second year.

Gardening Glossary
annuals
Plants that complete their entire life cycle within one growing season. The plant germinates from seed, grows and blooms, and then produces seed and dies.

Gardening Glossary
biennials
A plant that take two growing seasons to complete its life cycle. It germinates and grows leaves and stems in the first year; produces flowers and fruit (seed) in the second, and then dies.

Gardening Glossary
bolt
When a plant flowers or produces seed prematurely.

Gardening Glossary
cold frame
A wooden or concrete block box in which you can grow plants or hold dormant during the cold winter months.

Gardening Glossary
cole crops
A family of vegetables, including broccoli, cabbage, cauliflower, kale, and Brussels sprouts. They thrive in cooler weather.

Gardening Glossary
complete fertilizer
Any fertilizer that contains all three of the primary nutrients, N-P-K (nitrogen, phosphorus, potassium). Phrase is based on regulations governing the fertilizer industry. Does not mean that the fertilizer literally contains everything a plant needs to thrive.

Gardening Glossary
deadheading
The practice of pinching or cutting off spent flowers

Gardening Glossary
evaporative-pad humidifier
A humidifier in which fans blow across a moisture-laden pad that sits in a reservoir of water.

Gardening Glossary
harden off
The process of acclimating plants grown indoors gradually to the brighter light and cooler temperatures of the outside world.

Gardening Glossary
hardiness
The ability of a plant to survive is called its hardiness.

Gardening Glossary
humus
A stable end product of organic-matter decomposition that's believed to increase microbial activity in soil, improve soil structure, and enhance the root development of plants.

Gardening Glossary
Bacillus thuringiensis Bt
An effective bacteria that attacks only the larvae of caterpillar family insects. It is safe to other insects, animals, and humans.

Gardening Glossary
macronutrients
Mineral nutrients that plants need in the largest quantities: nitrogen, phosphorus, potassium, calcium, magnesium, and sulfur.

Gardening Glossary
mulch
Organic or inorganic material placed over the surface of soil, usually directly over the root zone of growing plants. Used to conserve moisture, kill weed seedlings, modify soil temperature, provide attractive covering to garden beds.

Gardening Glossary
organic matter
Once-living stuff like compost, sawdust, animal manure, ground bark, grass clippings, and leaf mold (composted tree leaves). Used to enrich soil and improve soil texture.

Gardening Glossary
perennials
Any plant with a life cycle of three or more years. Herbaceous (non-woody) perennials include flowering plants and herbs, mainly. Woody perennials include trees and shrubs. Longevity depends on the plant and growing conditions.

Gardening Glossary
pH
The measure of soil's acidity. Soil with low pH means it's too acidic; soil with high pH means it's alkaline. Most plants grow best in soil with a pH value between 6.5 and 7.2. Neutral soils measure 7.

Gardening Glossary
photosynthesis
The process through which plants take nutrients from the air and from the water in the soil to produce sugars that fuels the plant's growth.

Gardening Glossary
primary nutrients
Nitrogen, phosphorous, and potassium are the three nutrients plants need in the largest quantities.

Gardening Glossary
root crops
Plants with edible underground roots such as onions, carrots, beets, potatoes, turnips. Most root crops are cold-weather crops.

Gardening Glossary
self-blanching
A type of cauliflower with leaves that naturally curl over the head and exclude light. Requires cool temperatures for leaves to curl effectively.

Gardening Glossary
sets
Small onion bulbs, about 1/2-inch wide, that were started from seed the previous year. Grow onion sets with the pointy end up.

Gardening Glossary
side-dressing
The act of adding a small amount of fertilizer around or "on the side" of plants after they're growing.

Gardening Glossary
succession planting
Planting small, 2-to-4-foot patches of plants every two weeks throughout the growing season so that you can harvest a crop over an extended period of time.

Gardening Glossary
thinning
The act of cutting the least robust seedlings in your garden to give the healthier plants more room to grow.

Gardening Glossary
vining crops
Crops that grow on vines, such as cucumbers, melons, pumpkins, and winter squash. They usually require support (staking, trellising, etc.) to keep them off the ground.