How to Tell if Flower Bulbs Are Still Good: 7 Handy Tips

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Against a backdrop of red tulips, a white-crowned sparrow stands out with its gray, brown, and white plumage, creating a captivating image that highlights flower bulbs.

The journey to a healthy-looking garden starts with the perfect selection (and excellent care) of flower bulbs.

As we reach the perfect time for spring gardening, it’s only fitting to explore how to maintain different flower bulbs. It’s especially important when they are soft to the touch, moldy-looking, or completely dry.

In today’s guide, we’ll discuss how to tell if flower bulbs are still good so you can enjoy your flowers year after year.

Bulb Flower Types Every Gardener Needs to Know

Knowing the differences between bulb flower types has benefits and makes it much easier to arrange and grow a stunning garden that reflects your personality.

To help you bring your dream garden to life, we’ve explored the characteristics of the most popular types of bulbs below.

1. Spring Bulbs

Spring bulbs are also known as hardy bulbs, which reflect their tolerance for cold temperatures. They have protective scales and ‘tunic’ skin, features which make them resistant to not only cold temperatures but also to frost.

Spring bulbs will spend the winter in the ground and flower in the early spring. Please note that almost all spring bulbs need a cold winter to bloom.

Popular types include the following blooms:

  • Crocus.
  • Daffodils.
  • Tulips.
  • Irises.
  • Hyacinths.
Tulips in red, pink, yellow & purple hues bloom amidst verdant foliage, showcasing diverse flower bulbs.

2. Summer Bulbs

Summer bulbs are too tender to survive harsh winter conditions and are often referred to as tender bulbs.

We recommend that you avoid planting summer bulbs when it’s still cold and wet. If you plant during wintery conditions, your bulbs could potentially rot.

However, if planted at the right time, these bulbs will flower throughout the summer and even into fall.

Tip: Summer bulbs require a minimum soil temperature of 13°C to bloom, and more often than not, they also require full sun.

Some beautiful examples of summer-flowering bulbs include the following:

  • Dahlias.
  • Begonias.
  • Lilies.
  • Crocosmias.
  • Alliums.
A single yellow tulip contrasts with a multitude of closed green tulips, underscoring its individuality among flower bulbs.

3. True Bulbs

There is no singular bloom time for true bulbs.

True bulbs consist of five main parts: the basal plate, fleshy scales, the tunic, the shoot, and the lateral buds.

The basal plate sits at the bottom of the bulb and is where roots grow from. Then, there are fleshy scales surrounding the basal stem. These scales are responsible for the conservation of nutrients and energy.

To protect the fleshy scales, true bulbs have tunics that serve as a skin-like covering. True bulbs also have shoots, including leaf buds and the developing flower. Lastly, true bulbs have lateral buds, which are small baby bulbs that will develop into offsets.

There are two different types of true bulbs: tunicate bulbs and imbricate bulbs.

Tunicate bulbs have a tunic that prevents the bulb’s scales from drying out. This covering also protects the bulb from minor physical damage.

Imbricate bulbs don’t have a tunic covering. Keep imbricated bulbs moist before planting to ensure their scales don’t dry out.

Some of the most commonly planted true bulbs are:

  • Onions.
  • Garlic.
  • Tulips.
  • Lilies.
  • Daffodils.
Close-up shot of garlic bulbs and vibrant green stems illuminated naturally, featuring flower bulbs.

When to Plant Flower Bulbs

Knowing when to plant flower bulbs will help you keep your bulbs healthy.

As a general rule of thumb, you should plant spring-flowering bulbs during the fall. The best time to plant spring bulbs is between September and October.

The soil is still warm during these months, allowing the bulbs to produce new roots before the ground freezes. Make sure to plant the bulbs 6-8 weeks before the first hard frost in your area.

Tip: Tulips are the exception to this rule. We recommend planting tulips between November and early December. Generally, the weather is cold enough to prevent ‘tulip fire,’ a fungal disease that thrives in warm, damp conditions.

On the other hand, you should plant summer-flowing bulbs in spring between late February and early April. Planting summer bulbs during the springtime will help you protect your bulbs from the threat of frost.

Where to Plant Flower Bulbs

Different bulbs have different soil and location preferences.

For this reason, we recommend checking the requirements of your chosen variety.

However, there are some general tips you can use when deciding where to plant your flower bulbs. Most summer and spring-blooming bulbs, like daffodils and tulips, prefer a warm, sunny location and well-drained soil.

Some bulbs, like snowdrops and narcissi, will also grow in partial shade.

Most bulbs grow incredibly well in pots/containers.

As long as you follow your bulb’s unique soil, sunlight, and drainage requirements, you can plant them almost anywhere.

How to Plant Flower Bulbs

Below, we’ve revealed how you can effectively plant both spring bulbs and summer bulbs.

1. Knowing the Right Planting Depths

It’s important to plant your bulbs at the correct depth. Planting your bulbs too deeply can result in a lack of blooms while planting them too close to the soil’s surface will make them vulnerable to rodents like squirrels.

Typically, gardeners will plant their bulbs at three times their height. However, there are exceptions to that rule to bear in mind.

For spring bulbs, the ideal planting depth can range between four-twelve inches deep. Many summer bulbs can be planted at depths of four-six inches deep. For the likes of dahlias and nerines, plant the bulbs just below the surface.

Whichever flower bulb you intend to plant, ensure you’ve adjusted your planting depth according to their unique requirements.

2. Planting Bulbs in The Ground

First, make sure you are planting your bulbs in well-drained soil. If your soil is too heavy, consider adding organic matter like garden compost or chicken manure beforehand. Organic matter will help to improve soil drainage.

Using a trowel, dig a hole that is wide and deep enough to accommodate your bulbs. Place your bulbs in your planting holes, ensuring the pointed ends face upwards. Then, space out the bulbs at least twice the bulbs’ width apart.

Cover the bulbs back up with a layer of topsoil.

For spring bulbs, which ideally you’ll plant in autumn, you may not have to water them immediately as long as the soil is adequately moist. If you’ve opted for spring planting with summer bulbs, we recommend watering them when they are planted.

3. Planting Bulbs in Containers

Invest in a frost-resistant container that has drainage holes and enough depth to accommodate several inches of peat-free, multi-purpose compost.

Before you add your compost to your container, add some crocks to the base. By adding crocks to the bottom of your container, you’ll improve drainage.

Next, you can add your compost to the base of your container. From here,  add the bulbs, remembering to position the pointed ends upward.

In pots or containers,  plant your bulbs closer to one another and the compost’s surface. We recommend spacing your bulbs out at around 1-2 cm.

Now, all you need to do is top up your container with compost and water well. Ensure your bulbs’ tips are barely visible beneath the compost’s surface.

Beautiful bouquet of white tulips with vibrant green leaves against a soft gray backdrop, highlighting flower bulbs.

How to Care for Flower Bulbs

Now that you know how to plant your bulbs, we’ll address how to care for them.

1. Watering

Every type of bulb needs plenty of water as it grows. They also need plenty of water for up to six weeks after they’ve flowered until they become dormant.

Tip: Summer-flowering bulbs may need a touch more water during hot, dry spells.

If you’re growing your bulbs in containers, monitor them regularly to ensure they haven’t dried out over the growing period. You should water container-grown bulbs thoroughly, allowing the soil to become slightly damp before the next watering. The goal is to make the compost moist but not waterlogged and soggy.

2. Fertilizing

Every 7-10 days, fertilize your bulbs with a balanced or high-potassium fertilizer (like a liquid tomato feed).

Fertilize your bulbs when their shoots start appearing, then stop when your bulbs’ foliage starts to die.

For bulbs in containers, the fertilizer requirements are almost the same. The only difference is that you should use your high-potassium fertilizer before flowering.

3. Overwintering

You can leave spring bulbs in the ground or their containers all year round.

For tender summer bulbs that are grown in containers, we recommend bringing them inside over winter. If you live in a warm/mild enough region, you could potentially leave them in the ground over winter. However, the bulbs could risk succumbing to frost or rotting in soggy soil conditions.

When leaving your summer bulbs in the ground, make sure you have light, well-draining soil. We also suggest you cover them in an eight-ten inch layer of insulating mulch. Removing the mulch in spring when your bulbs start to grow.

How to Tell if Flower Bulbs Are Still Good: Tips and Tricks

Knowing how to tell if flower bulbs are still good is essential. Below, we’ve listed a few tips and tricks to help you evaluate the health of your bulbs.

  • A healthy bulb is plump and firm to the touch. If your bulbs feel soft and mushy, they have rotted and must be discarded.
  • An unhealthy bulb will have a dried-out, moldy-looking appearance.
  • Conduct a ‘bucket test’ by filling a bucket with water and a half-dozen of your bulbs. Healthy bulbs will sink. Rotten bulbs have lighter interiors, which makes them float. Discard any bulbs that float and dry off the remaining healthy bulbs if you intend to put them back in storage.
  • If your bulbs have dark discolorations, soft spots, or a slimy texture, they may have a fungal or bacterial infection. Discard bulbs that show these symptoms immediately.
  • Discard any bulbs that look as if they have burrowed tunnels. This can be a sign of pest damage, in which case, they won’t grow effectively, if at all.
  • Monitor the age of your flower bulbs. Most individual bulbs have a lifespan between 2-5 years in the garden. After this point, your bulbs will naturally stop blooming.
  • Any unplanted bulbs that you have kept in storage for longer than 12 months probably won’t bloom well either.

By planting and maintaining your bulbs effectively, you shouldn’t encounter such issues.

The Best Spring Flower Bulbs To Plant

We’ve revealed some of our favorite spring flower bulbs to help you arrange a stunning spring garden.

  1. Daffodils.
  2. Hyacinths.
  3. Crocus.
  4. Snowdrops.
  5. Tulips.
  6. English Bluebells.
  7. Anemones.
  8. Snakes Head Fritillary.
Bright yellow daffodils with orange centers arranged in clear glass vase, showcasing flower bulbs.

The Best Summer Flower Bulbs To Plant

As we did with spring bulbs, we’ve also unveiled our top picks for beautiful summer flower bulbs.

  1. Begonias.
  2. Freesias.
  3. Dahlias.
  4. Bearded Irises.
  5. Alliums.
  6. Lilies.
  7. Peacock Orchids.
  8. Gladiolis.
Red geraniums bloom in terracotta pots on rustic stone steps, alongside fallen apples, with a wooden fence backdrop, flower bulbs.

Thriving Flower Bulbs: Final Thoughts

When you know how to tell if flower bulbs are still good, you will know how to nurture a beautiful flower garden year after year.

By following our advice, you won’t have to deal with unusable bulbs. Instead, you’ll be able to enjoy a colorful, diverse garden throughout the gorgeous spring and summer months.

For more advice on plant growth and care and all things gardening, check out our blog!

Frequently Asked Questions

Our most frequently asked questions relating to flower bulbs.

1. What are the first spring bulbs to flower?

Spring bulbs such as snowdrops and scillas are some of the earliest flowering plants to incorporate into your garden, blooming in very early spring.

2. Do summer bulbs multiply?

Simply put, the answer is yes. Summer bulbs, like many other bulbs, multiply by producing offsets and do so without any input from gardeners. This means that it’s incredibly easy to grow more of your favorite bulbs.

3. Which bulbs bloom the longest?

The bulbs that bloom for the longest period of time are Darwin and Triumph tulips. Darwin and Triumph tulips are hybrids that are bred to bloom for an impressive amount of time – these tulips can last for a month or longer!

4. What happens if you plant bulbs at the wrong time?

If you decide to plant your bulbs outside of their optimal planting periods, more often than not, the temperature of the soil will most often impact the quality of the bulb’s flowering. In some cases, you may notice certain deformities in the flower, and in other cases, the flower won’t grow at all.

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