Ox Tongue Care

Best Light for Ox Tongue (Gasteria)

Here's where Gasteria breaks the mold compared to basically every other succulent. Where your Aloe Vera or a typical Echeveria wants intense direct sunlight, Gasteria is naturally adapted to filtered and indirect light.

In its native habitat along the Eastern Cape of South Africa, Gasteria grows tucked under shrubs, rocks, and cliff overhangs where it receives dappled shade for most of the day. This makes it one of the very few succulents you can confidently place in:

• Bright indirect light (the sweet spot for fastest growth)
• Medium indirect light (still does great on a desk or shelf)
• Low light conditions (it will survive, though growth slows noticeably)
• East or north-facing windows are ideal indoor spots

Some direct morning sun is fine, especially from an east-facing window. But avoid harsh afternoon sun, particularly through south or west-facing windows in summer. Unlike most succulents, Gasteria sunburns easily.

For a more detailed breakdown of indoor light levels, have a look at our indoor light guide. And if you're dealing with shorter days during the colder months, our article on providing enough light during winter has some practical tips that apply here too.

Signs of Incorrect Lighting for Ox Tongue

Too Much Light:

• Leaves turning reddish, brown, or bleached (sunburn)
• Dry, crispy patches on leaf surfaces
• Leaves looking washed out or faded
• Plant appears stressed and stops growing

Too Little Light:

• Leaves become elongated and thin (etiolation)
• Plant stretches toward the light source
• Loss of the compact, stacked leaf arrangement
• Color fades to pale green
• Very slow or no new growth over months

If you notice your Gasteria stretching, don't move it into direct sun all at once. Transition it gradually over 1-2 weeks to avoid shock. For tips on managing the transition when bringing a new plant home, check out our beginner's walkthrough.

Watering Needs for Ox Tongue

If there's one thing that kills Gasteria faster than anything else, it's overwatering. These are true succulents with thick, fleshy leaves designed to store water for dry periods. They'd rather be bone dry for a week than sit in damp soil for two days straight.

The golden rule: soak and dry. Water deeply until it runs out the drainage hole, then don't water again until the soil has dried out completely. Stick your finger two inches into the soil. If there's any dampness at all, wait. If you're uncertain, a moisture meter takes the guesswork out of it.

How Often to Water Ox Tongue

• Spring and Summer (growing season): Every 2-3 weeks, depending on your pot size, temperature, and humidity
• Fall and Winter (semi-dormancy): Once a month or even less. The plant's growth slows to a crawl, and it uses very little water

These are rough guidelines. A small terracotta pot in a warm, bright spot will dry out much faster than a large ceramic pot in a cool room.

For winter-specific watering advice, our article on how to water houseplants in winter covers the adjustments you'll want to make.

How to Water Ox Tongue Correctly

Top Watering (Recommended):

1. Water at the soil level, keeping water out of the leaf rosette
2. Soak until water drains freely from the bottom holes
3. Empty the saucer completely after 15-20 minutes. Never let the pot sit in standing water.

Bottom Watering Alternative:
Bottom watering works well for Gasteria since it keeps water away from the leaf bases where rot can start. Set the pot in a shallow tray of water for 15-20 minutes, letting the soil absorb moisture from below, then remove and drain.

Water Temperature: Use room-temperature water. Cold water isn't ideal for any houseplant, but Gasteria handles it better than most tropicals.

Signs of Watering Problems in Ox Tongue

Overwatering (the bigger danger):

• Leaves turn yellow, translucent, or mushy
• Soft, squishy texture when gently squeezed
• Black or brown spots at the leaf base
• Musty smell from the soil
• Plant falls apart when touched

Underwatering:

• Wrinkled, concave leaf surfaces
• Leaves feel thinner and less plump
• Tips drying out and turning brown
• Very slow growth (even during spring/summer)

Honestly, underwatering is much easier to fix. A good soak will usually plump wrinkled leaves back up within a day or two. Overwatering damage is often irreversible by the time it's visible.

What Soil Does Ox Tongue Need?

Fast drainage is the priority with Gasteria. Standard potting soil holds far too much moisture and will lead to root rot. You need something gritty, chunky, and free-draining.

The ideal soil mix is:

• Extremely well-draining (water should flow through within seconds)
• Mostly inorganic material (perlite, pumice, coarse sand)
• Low in organic matter (minimal peat or compost)
• Slightly acidic to neutral pH (5.5-7.0)

For a deeper dive into getting your soil mix right, our soil guide covers the fundamentals.

DIY Soil Mix Recipe for Ox Tongue

Here's what works well for Gasteria:

Basic Mix:

• 1 part quality cactus/succulent potting mix
• 1 part perlite or pumice
• 1 part coarse sand (horticultural grade, not beach sand)

Grittier Mix (for humid climates or chronic overwaterers):

• 1 part potting soil
• 2 parts pumice or perlite
• 1 part coarse sand or fine gravel

The ratio of inorganic to organic material matters more than the exact ingredients. You want the soil to dry within a few days, not hold moisture for a week.

Pre-Made Soil Options for Gasteria

If mixing your own soil sounds like too much work:

• Any commercial cactus and succulent mix will work as a base, but add extra perlite
• Bonsai soil (akadama-based) is surprisingly well-suited
• Avoid anything labeled "moisture control" or "water-retaining"

The cheaper bagged "cactus mixes" from garden centers are often still too heavy on their own. Cutting them 50/50 with perlite makes a noticeable difference.

Does Ox Tongue Need Fertilizer?

Gasteria is a light feeder that does fine without much fertilizing at all. In the wild, it grows in rocky, nutrient-poor soil and it's adapted accordingly. That said, a little food during the growing season encourages healthier growth and can help trigger blooming.

Think of fertilizer as a gentle boost, not a requirement. A healthy Gasteria in decent soil will chug along without any extra feeding for years.

When and How to Fertilize Ox Tongue

• Growing Season (Spring through early Fall): Feed once a month with a balanced or succulent-specific liquid fertilizer diluted to half the recommended strength
• Winter: Stop all fertilizing. The plant isn't actively growing and excess nutrients will just accumulate in the soil as salts

Best Fertilizer Types for Gasteria:

• Liquid succulent/cactus fertilizer (the easiest option)
• Balanced houseplant fertilizer (10-10-10) diluted to quarter or half strength
• Slow-release granules applied once in spring (less control but convenient)

Always fertilize moist soil, never dry. For more guidance, see our fertilizing guide. And if you're curious about adjusting your feeding routine as the seasons change, our article on winter fertilizing rules breaks down when to stop and start.

Signs of Fertilizer Problems in Ox Tongue

Over-Fertilization:

• White salt crusty deposits on soil surface or pot edges
• Brown leaf tips
• Sudden leaf drop or softening

Under-Fertilization (rare, but possible after years in the same soil):

• Very pale new growth
• Extremely slow growth even in growing season
• Leaves smaller than normal

If you've overdone it, flush the soil by running water through the pot several times to wash out the excess salts.

Ideal Temperature for Ox Tongue (Gasteria)

Gasteria handles a surprisingly wide temperature range, which is part of what makes it so easy. It's comfortable in typical household temperatures and can tolerate brief cold snaps that would damage many other houseplants.

Ideal Range: 60-80°F (15-27°C)

That covers pretty much every normal indoor environment. The plant will keep ticking along even outside this range, just with slower growth.

Temperature Tolerance for Gasteria

• Minimum: Can tolerate brief dips to about 40°F (4°C), but prolonged cold below 50°F (10°C) isn't ideal
• Maximum: Handles heat well if kept out of direct sun. Temperatures above 90°F (32°C) can stress the plant, especially if combined with bright light
• Sweet Spot: 65-75°F (18-24°C) for the best growth

What to Avoid:

• Frost (Gasteria is not frost-hardy)
• Placement directly against cold windowpanes in winter
• Drafty spots near exterior doors
• Right above radiators or heating vents

If your home tends to get quite hot in summer, our article on how to protect indoor plants from summer heat has some practical workarounds. On the flip side, Gasteria is highlighted in our heat-loving houseplants roundup for its tolerance of warm conditions (as long as light is managed).

A cooler winter rest (around 50-60°F) can actually be beneficial, as it helps trigger flowering in spring. Just keep it dry during the cold period.

Does Ox Tongue Need High Humidity?

Nope. This is one of the most humidity-tolerant plants you can grow. Coming from the semi-arid regions of South Africa, Gasteria is completely at home in the dry air of a typical house, apartment, or office.

Ideal Humidity: 30-50% (normal household levels)

You don't need a humidifier, pebble tray, or any special setup. Standard indoor air is just fine. In fact, very high humidity (above 70%) combined with poor airflow can actually be a problem, as it encourages fungal issues.

If you're looking for plants that thrive in dry air specifically, Gasteria is the opposite of what you'd find in our humidity-loving plants guide, and that's a plus for anyone who doesn't want to fuss with humidity trays.

Humidity Considerations for Ox Tongue

While Gasteria is generally unfussy about humidity:

• Very dry air (below 20%, common during winter with central heating) won't damage it, but leaf tips might dry out slightly
• Very humid environments (bathrooms, terrariums) are fine as long as there's good air circulation and the soil dries properly
• Avoid misting. Unlike tropical plants, Gasteria doesn't benefit from misting at all. Water sitting on leaves and in the leaf rosette just invites rot

For general humidity management tips, check out our humidity guide.

What Do Ox Tongue Flowers Look Like?

Gasteria flowers are genuinely charming and unlike most succulent blooms. The plant sends up a long, arching flower stalk (sometimes 2-3 feet tall on larger species) lined with small, tubular flowers that are slightly swollen at the base. This belly-shaped flower is actually where the name "Gasteria" comes from (Latin "gaster" meaning stomach).

The flowers are typically:

• Pink, coral, orange, or red on the outside
• Greenish tips with a slight curve
• Arranged along one side of the stalk in a raceme
• Attractive to hummingbirds and sunbirds in their native habitat

Blooming usually happens in late winter through spring, and the flower stalk can last for several weeks.

How to Encourage Gasteria to Flower

Mature plants (typically 3+ years old) will flower fairly reliably if given:

1. A cooler winter rest: Drop temperatures to 50-60°F (10-15°C) for 4-6 weeks
2. Reduced winter watering: Keep the plant relatively dry during this cool period
3. Bright indirect light: Especially important in the weeks before and during blooming
4. Light spring feeding: A dose of fertilizer as temperatures warm up can help fuel the flower stalk

Indoor-grown Gasteria won't always flower, and that's perfectly normal. The conditions need to align, and some species are more reluctant bloomers than others. Don't stress about it. The foliage is the real draw.

Ox Tongue After Blooming Care

Once flowers fade, cut the spent stalk at its base with clean scissors. This redirects energy back to leaf and offset production. Blooming can be slightly exhausting for the plant, so a light feed after flowering finished helps it recover.

If your flower stalk produces seeds, you can try growing them, but seed-raised Gasteria takes years to mature. Offsets are a much faster way to get new plants.

Popular Gasteria Species and Cultivars

There are around 80 recognized Gasteria species, and they vary quite a bit in size and leaf shape. Here are the ones you're most likely to find at nurseries:

Gasteria obliqua (formerly G. bicolor var. liliputana)
Probably the most common houseplant Gasteria. Compact, with dark green tongue-shaped leaves covered in dense white spots and tubercles. Stays fairly small (4-6 inches), making it perfect for windowsills and desks.

Gasteria batesiana
Has beautifully rough, almost sandpaper-like leaf texture with a dark green, nearly black coloring. Forms a tight rosette rather than the typical two-ranked arrangement. One of the more visually striking species.

Gasteria carinata
Features heavily spotted, keeled (triangular cross-section) leaves. A very forgiving species that offsets freely.

Gasteria 'Little Warty'
A popular hybrid with thick, bumpy leaves absolutely covered in raised white tubercles. Stays compact and produces offsets generously. The "warty" look is actually what makes this one so collectible.

Gasteria glomerata
One of the smallest species, rarely exceeding 3 inches. Thick, stubby leaves stacked tightly together. Great for tiny pots and terrarium displays.

Intergeneric Hybrids:
Gasteria crosses readily with both Aloe and Haworthia, producing:

• ×Gasteraloe (Gasteria × Aloe): Combines the shade tolerance of Gasteria with Aloe's form
• ×Gasterworthia (Gasteria × Haworthia): Usually compact with mixed features from both parents

How to Tell Gasteria Apart from Similar Plants

Gasteria, Haworthia, and Aloe are closely related (all in the Asphodelaceae family) and often confused. Here's the quick cheat sheet:

• Gasteria: Thick, tongue-shaped leaves, often in a distichous (two-ranked, flat fan) arrangement when young. Stomach-shaped tubular flowers. Raised white tubercles common.
• Haworthia: Thinner, more triangular leaves in tighter rosettes. Often has translucent leaf windows. Smaller flowers.
• Aloe: Generally larger, thicker upright leaves with teeth or spines along margins. Tubular flowers but not stomach-shaped.
• African Spear (Sansevieria cylindrica): Sometimes confused due to the common name, but completely different genus (Asparagaceae family) with cylindrical, upright leaves.

When plants are young, even experienced collectors can struggle telling them apart. The distichous (flat, two-ranked) leaf arrangement is the most reliable Gasteria giveaway.

When to Repot Ox Tongue

Gasteria has a small, relatively shallow root system and doesn't mind being somewhat potbound. In fact, slightly tight containers help prevent overwatering by reducing the volume of wet soil around the roots.

Repot every 2-3 years, or when:

• Offsets are crowding the pot and pushing against the sides
• Roots are growing out of the drainage hole
• The soil has broken down and no longer drains quickly
• The plant is visibly top-heavy or tipping over

Spring is the best time to repot, just as the growing season kicks off.

How to Repot Ox Tongue

1. Choose the Right Pot: Only go 1 inch larger in diameter. Too big a pot means too much wet soil. Shallow, wider pots work better than deep ones for Gasteria's shallow root system.
2. Drainage is Mandatory: Always use pots with drainage holes. Terracotta is ideal because it breathes and helps soil dry faster.
3. Remove Carefully: Gently slide the plant from its old pot. Shake off old soil and inspect the roots.
4. Trim if Needed: Remove any dead, black, or mushy roots with clean scissors.
5. Replant at the Same Depth: Don't bury the leaves or crown deeper than before. Fill with fresh succulent mix.
6. Wait to Water: Unlike most houseplants, don't water immediately after repotting. Wait 3-5 days to let any disturbed roots heal. This prevents rot.

For a more detailed walkthrough, see our repotting guide.

Best Pots for Ox Tongue

• Terracotta: The best option. Porous walls wick moisture away from the soil, reducing rot risk.
• Unglazed Ceramic: Similar benefits to terracotta, slightly more decorative.
• Shallow Dishes and Bowls: Great for planted arrangements with other succulents. Drill drainage holes if they don't have them.
• Avoid: Pots without drainage holes, glass containers without drainage, or anything that traps moisture.

Does Ox Tongue Need Pruning?

Gasteria requires almost zero pruning. It's a slow-growing rosette plant that maintains its own shape naturally. Pruning is really only necessary for cleanup or health reasons.

When to Prune:

• Remove dead, dried, or damaged leaves
• Cut away any leaves showing signs of rot (soft, mushy, discolored tissue)
• Trim spent flower stalks after blooming
• Separate offsets when the pot becomes overcrowded

How to Prune Ox Tongue

• Tools: Clean, sharp scissors or a small knife. Sterilize with rubbing alcohol before and after.
• Technique: Cut dead or damaged leaves as close to the base as possible without injuring surrounding healthy tissue.
• Rotting Leaves: If you spot soft, mushy leaves, remove them immediately. Check the base of the plant and the roots for further rot. You may need to unpot and address the issue.
• Timing: Any time of year, though the plant recovers from any disturbance faster during the growing season (spring/summer).

Let any wound or cut dry and callus over before watering to prevent infection.

Why Gasteria is Easy to Propagate

Gasteria is one of the most cooperative succulents for propagation. Mature plants produce offsets (pups) freely, which is the simplest and most reliable method. But you can also grow entirely new plants from single leaf cuttings, which is pretty satisfying to watch.

For a broader look at succulent propagation techniques, our succulent propagation guide covers the general principles. And for more on propagation fundamentals, see our propagation hub.

Method 1: Propagating Ox Tongue by Offsets (Pups)

This is the easiest and fastest route to a new Gasteria. Most healthy, mature plants will produce small offsets around their base.

1. Wait for Size: Let pups grow to at least 1-2 inches before separating. Larger pups root faster and have better survival rates.
2. Remove from Pot: Unpot the mother plant and gently separate the offset. It should have some roots of its own. If it's still attached, use a clean, sharp knife to cut it free.
3. Let it Dry: Leave the separated offset in a dry, shaded spot for 1-2 days so the cut wound calluses over.
4. Plant in Dry Mix: Pot the offset in a small container of fresh, dry succulent mix. Don't water for 5-7 days.
5. Begin Normal Care: After a week, start watering lightly. The pup should establish its own root system within 2-4 weeks.

This is essentially the same process as plant division but on a smaller scale.

Method 2: Propagating Ox Tongue from Leaf Cuttings

Leaf propagation takes longer (months rather than weeks) but it works and lets you create multiple plants from a single parent.

1. Choose a Healthy Leaf: Select a firm, plump leaf. Gently twist or cut it cleanly from the base. A clean break with no tissue left behind is best.
2. Callus the Leaf: Place it in a dry, shaded spot for 3-5 days until the cut end forms a dry callus.
3. Lay on Soil: Place the callused leaf on its side on top of slightly moist succulent mix. Partially bury the cut end if you prefer.
4. Wait Patiently: In 4-8 weeks, you should see tiny roots and eventually a small plantlet forming at the base of the leaf. Mist sparingly during this period.
5. Pot Up: Once the new plantlet is about half an inch and has its own root system, pot it individually.

The parent leaf will eventually shrivel and dry out as the baby plant absorbs its stored energy. This is completely normal, so don't remove it until it comes away on its own.

Method 3: Propagating Ox Tongue by Seed

Seed propagation is possible if your plant produces viable seed, but it's slow. Gasteria seeds need:

• A warm, humid environment (a covered seed tray works)
• Light, well-draining seed-starting mix
• Patience: germination takes 2-4 weeks, and seedlings grow very slowly
• Years to reach mature size

For most people, offsets and leaf cuttings are far more practical.

Common Pests Affecting Ox Tongue (Gasteria)

Gasteria is quite pest-resistant overall, but no plant is completely immune. The most common visitors:

Mealybugs: The most likely pest you'll encounter. They look like tiny white cottony clusters, often hiding in the leaf axils and between tightly stacked leaves. Check the base of the rosette where leaves overlap, as they love dark, sheltered spots. Treat by dabbing with a cotton swab soaked in rubbing alcohol, or spray with insecticidal soap.

Scale Insects: Appear as small brown or tan bumps on leaves. They attach firmly and suck sap, weakening the plant over time. Scrape them off gently with a fingernail or old toothbrush, then treat the area with neem oil or rubbing alcohol.

Fungus Gnats: The tiny black flies that hover around damp soil. They're more of a nuisance than a real threat to Gasteria, and they're almost always a sign of overwatering. Let the soil dry out more thoroughly between waterings and use yellow sticky traps to catch adults.

Preventing Pest Problems on Gasteria

• Inspect new plants carefully before adding them to your collection
• Quarantine new arrivals for 2 weeks
• Don't overwater (soggy soil attracts fungus gnats and creates favorable conditions for mealybugs)
• Ensure good air circulation
• Clean leaves periodically by wiping with a damp cloth
• Check between tightly stacked leaves regularly, as pests love hiding in those crevices

Common Ox Tongue Problems and Solutions

Mushy, Translucent, or Yellow Leaves
The number one problem, and it's almost always overwatering. The leaves store water, so when the roots are sitting in too much moisture, the excess gets pushed into the leaves until cells rupture. By the time leaves go mushy, the roots may already be rotting.

• Check roots immediately. Trim anything black or mushy.
• Repot in completely dry, fresh succulent mix
• Don't water for at least a week after repotting
• Going forward, reduce watering frequency significantly

Sunburn and Leaf Scorch
Gasteria is more sensitive to direct sun than most succulents. Scorched leaves show bleached white or brown dry patches, sometimes with reddish-purple stress coloring.

• Move to a more shaded spot immediately
• Damaged tissue won't heal, but the plant will grow new healthy leaves
• Transition to brighter light gradually over 1-2 weeks if you want to increase exposure

Wrinkling or Shriveling Leaves
This one actually means your Gasteria is thirsty (the opposite of mushy leaves). The leaves lose their plumpness and develop visible wrinkles or concave surfaces.

• Give a thorough soak and the leaves should plump back up within a day or two
• If wrinkles persist after watering, the roots may be damaged and unable to absorb water. Check for root rot.

Leggy, Stretched Growth (Etiolation)
The leaves become thin, elongated, and spaced apart instead of compact and stacked. This is the plant reaching for more light.

• Move to a brighter location with more indirect light
• You can't reverse existing stretched growth, but new growth will be compact in better conditions

Diseases That Affect Ox Tongue

Root Rot
The most common disease, directly caused by overwatering and poor drainage. Symptoms include soft stems, mushy leaf bases, and a rotten smell from the soil.

• Unpot, trim all affected roots, let the plant dry for 1-2 days, and replant in fresh soil with improved drainage
• Severely rotted plants may need to be propagated from surviving healthy leaves

Fungal Infections
Black or brown spots on leaves that spread, often with a wet or slimy appearance. Usually caused by water sitting on leaves combined with poor air circulation.

• Remove affected leaves
• Improve airflow around the plant
• Apply a fungicide if the infection persists
• Avoid wetting the foliage when watering

Best Ways to Display Ox Tongue (Gasteria)

Gasteria's compact size and low-light tolerance make it one of the most versatile succulents for indoor styling. It fits places where most succulents can't go.

Desktop and Shelf Plant
Gasteria's small footprint makes it perfect for desks, bookshelves, nightstands, and bathroom counters. It doesn't need to be by a window, so you can place it almost anywhere that gets reasonable ambient light.

Succulent Arrangements
Group your Gasteria with other shade-tolerant succulents like Haworthia and small Aloe species for a stunning South African-themed collection. All three have very similar care needs, so they work perfectly together in a single planter.

Terrariums
Open terrariums are a great fit. The slightly higher humidity won't bother Gasteria as long as there's ventilation and the soil drains well. Avoid closed terrariums, as the moisture buildup is too much.

Windowsill Collections
East or north-facing windowsills are ideal. Line up a collection of different Gasteria species in matching small pots for a clean, structured look.

Ox Tongue Styling Tips

• Container Choice: Textured, earthy pots (terracotta, concrete, rough ceramic) complement Gasteria's rugged, bumpy leaves beautifully
• Group by Genus: A collection of Gasteria, Haworthia, and Aloe creates a visually interesting display with minimal care variation
• Modern Minimalism: A single Gasteria in a simple concrete pot on a clean desk is quietly elegant
• Contrast Textures: The bumpy, warty leaf texture pairs well with smooth-leaved plants nearby
• Scale Matters: Use Gasteria's small size to fill gaps in larger plant collections or to add interest to compact spaces

Is Ox Tongue (Gasteria) safe for cats and dogs?

Yes! Gasteria is completely non-toxic to cats and dogs, making it one of the best pet-safe succulents you can grow indoors. Unlike many succulents in the Euphorbia family, Gasteria poses no risk to curious pets.

Can Ox Tongue grow in low light?

Absolutely. Gasteria is one of the rare succulents that genuinely handles low light conditions well. In the wild, it grows under shrubs and rock overhangs in partial shade. While it will grow a bit faster in bright indirect light, it won't stretch or suffer in a north-facing window or on a desk away from direct sun.

How often should I water my Ox Tongue plant?

Water your Gasteria only when the soil is completely dry, typically every 2-3 weeks in spring and summer and once a month or less in winter. Overwatering is the number one killer of these plants, so when in doubt, wait a few more days.

Why is my Ox Tongue turning yellow or mushy?

Yellow, translucent, or mushy leaves are almost always a sign of overwatering or root rot. Remove the plant from its pot, trim any rotten roots, let it dry for a day, and repot in fresh, dry succulent mix. Cut back on watering going forward.

What is the difference between Gasteria, Haworthia, and Aloe?

All three belong to the Asphodelaceae family and look similar, but they have distinct differences. Gasteria has thick, tongue-shaped leaves often arranged in two rows (distichous) with raised white bumps (tubercles). Haworthia tends to have thinner, more triangular leaves in tighter rosettes. Aloe typically grows larger with thicker, more upright leaves that have teeth along the margins. All three are easy to care for and can even hybridize with each other.

How do I get my Ox Tongue to flower?

Mature Gasteria plants (usually 3+ years old) will bloom on their own if given the right conditions. Provide bright indirect light, a cooler winter rest period with reduced watering, and a bit of fertilizer in spring. The tubular pink-to-red flowers appear on long, arching stalks, usually in late winter or early spring.