Brussels Sprouts Long Island Improved Vegetable Seeds

Brussels Sprouts Long Island Improved Vegetable Seeds

Botanical Name: Brassica oleracea var. gemmifera

---

Long Island Improved is a classic heirloom Brussels sprouts variety producing numerous firm, compact green sprouts along sturdy upright stalks. Introduced in the late 19th century, this dependable open-pollinated variety remains popular with home gardeners for its traditional Brussels sprout flavour, productive plants and relatively compact growth habit.

The medium-green sprouts develop progressively from the bottom of the stalk upwards and are best harvested when firm and tightly formed. Individual sprouts typically reach approximately 2.5–3.5 cm in diameter, making them an excellent size for roasting, steaming, sautéing, boiling and freezing.

Brussels sprouts are a cool-season vegetable and produce their best quality when the sprouts mature during cool autumn and winter conditions. Long Island Improved is particularly well suited to Australian winter vegetable gardens, with planting times adjusted according to climate so that the developing sprouts avoid excessive heat.

Key Attributes

Product Description

Long Island Improved is one of the best-known traditional Brussels sprout varieties, valued for its dependable production of firm green sprouts and comparatively compact plants. Developed from older strains of Brussels sprouts and established as a garden variety by the late 1800s, it predates the modern F1 hybrids commonly used in intensive commercial production.

Plants develop a strong central stalk surrounded by broad blue-green to medium-green leaves. As the plants mature, small cabbage-like buds begin forming in the leaf axils along the stalk. These buds gradually enlarge into the familiar Brussels sprouts harvested for eating.

The lower sprouts mature first, followed progressively by those further up the stalk. This allows gardeners to harvest mature sprouts over an extended period rather than removing the entire crop at once.

Long Island Improved generally produces firm green sprouts approximately 2.5–3.5 cm in diameter under suitable growing conditions. Plant height is comparatively compact for a Brussels sprout, commonly around 45–60 cm, although final size depends on climate, soil fertility, spacing and growing conditions.

This is a true cool-season vegetable. Although the plants require a relatively long growing period, the best sprouts develop when the later stages of growth occur during cool weather. Prolonged hot conditions can result in loose sprouts and stronger or more bitter flavour.

For Australian gardeners, this means timing the crop backwards from the cooler months rather than simply treating Brussels sprouts as a conventional spring vegetable.

In temperate and many subtropical areas, seedlings are commonly established from late summer into autumn for development through autumn and winter. In colder districts, sowing can begin earlier so that plants have sufficient time to mature before severe winter conditions.

Long Island Improved is an open-pollinated heirloom variety, rather than an F1 hybrid. Plants may therefore show somewhat more natural variation than highly uniform commercial hybrids, but the variety remains popular for home production, traditional vegetable gardens and seed-saving gardens.

Why Grow Long Island Improved Brussels Sprouts?

• Classic heirloom Brussels sprout variety dating to the 1890s.
• Traditional open-pollinated, non-hybrid variety.
• Produces firm, compact medium-green sprouts.
• Sprouts commonly reach approximately 2.5–3.5 cm in diameter.
• Productive central stalk with numerous developing sprouts.
• Sprouts mature progressively from the bottom upwards.
• Provides an extended harvest period.
• Relatively compact plant compared with many taller Brussels sprout varieties.
• Traditional rich Brussels sprout flavour.
• Excellent cool-season vegetable.
• Suitable for autumn and winter vegetable gardens.
• Excellent for roasting, steaming, sautéing and boiling.
• Suitable for freezing.
• Well suited to home vegetable gardens and market gardens.
• Good choice for gardeners interested in heirloom vegetable varieties.

Plant Details

Sowing Information

When to Sow Long Island Improved Brussels Sprouts in Australia

These sowing periods are general guides. Brussels sprouts are strongly influenced by local temperature, so planting should be timed to allow the plants to establish before producing their sprouts during the coolest practical part of the season.

How to Grow Long Island Improved Brussels Sprouts

Choose an open position receiving full sun. Brussels sprouts are long-season brassicas and require fertile soil, consistent moisture and sufficient space to develop strong stalks and root systems.

Prepare the planting area before transplanting. Remove weeds and incorporate well-decomposed compost or another suitable organic soil amendment where required.

Brussels sprouts generally prefer a slightly acidic to near-neutral soil and perform poorly where drainage is inadequate.

Sow seeds approximately 5–10 mm deep in seedling trays, punnets or a prepared seed bed.

Keep the growing medium evenly moist during germination.

Once seedlings have developed several true leaves and are approximately 4–6 weeks old, transplant the strongest plants into their final positions.

Space plants approximately 45–60 cm apart. Allow around 75–100 cm between rows where space permits.

Plant seedlings firmly. Brussels sprouts eventually develop a substantial central stalk carrying considerable weight, so a well-established root system is important.

Water thoroughly after transplanting.

Maintain even soil moisture as the plants grow. Avoid allowing plants to repeatedly wilt and recover, as inconsistent growth can affect the formation and quality of the sprouts.

Keep weeds under control, particularly while plants are young.

As plants mature, small buds will begin developing between the leaves and central stem. These enlarge to form the Brussels sprouts.

Growing Brussels Sprouts in Australian Conditions

Brussels sprouts have a reputation for being difficult in Australia, but the main issue is usually temperature and planting time rather than the crop itself.

They require a long period of vegetative growth followed by sufficiently cool conditions for tight, high-quality sprouts to develop.

If planted too early in warm climates, the developing sprouts may be exposed to excessive heat.

If planted too late in cold climates, the plants may not have enough time to develop before winter slows growth substantially.

The ideal strategy is therefore to work backwards from the expected cool season.

In southern and cool-temperate regions, plants can be established during summer and allowed to mature into autumn and winter.

In warmer subtropical regions, late-summer and autumn sowings are usually more appropriate.

In genuinely tropical lowland conditions, Brussels sprouts can be challenging because temperatures may remain too high for optimum sprout formation even during winter.

Why Cool Weather Matters

Brussels sprouts are members of the cabbage family and are naturally adapted to cool growing conditions.

The plants themselves can tolerate considerable cold once established.

Cool temperatures during sprout development generally encourage firmer heads and better eating quality.

Hot conditions can cause sprouts to remain loose rather than forming tightly packed miniature heads.

The flavour of Brussels sprouts is also often considered sweeter and more pleasant following exposure to cool conditions.

For this reason, Long Island Improved should be treated primarily as an autumn and winter vegetable in much of Australia.

Soil Preparation

Brussels sprouts remain in the garden for several months, so preparing the soil properly before planting is worthwhile.

The ideal soil is:

• Fertile
• Well drained
• Moisture retentive
• Rich in organic matter
• Firm enough to support mature plants
• Approximately slightly acidic to neutral in pH

Incorporate well-decomposed compost before planting where the soil requires additional organic matter.

Avoid planting into freshly cultivated, extremely loose soil without firming around the seedlings. A stable root system helps support the tall central stem.

Brassicas can be affected by clubroot in contaminated soils. Maintaining appropriate soil pH and crop rotation can form part of a broader management strategy, but affected sites may require specific disease-management measures.

Transplanting Brussels Sprout Seedlings

Long Island Improved is particularly well suited to starting in trays or punnets.

Raising seedlings separately allows growers to protect young plants from pests and select strong seedlings before planting into the main vegetable garden.

Transplant once plants have developed several true leaves and are sufficiently sturdy to handle.

Water seedlings before transplanting.

Make a planting hole large enough to accommodate the root system without forcing the roots into a tight mass.

Place the seedling into the hole and firm the surrounding soil gently but thoroughly.

Water immediately after planting.

For the first several days, monitor newly transplanted seedlings carefully for drying, particularly during warm or windy weather.

Spacing Brussels Sprouts

Do not crowd Brussels sprouts.

Although Long Island Improved is relatively compact, each plant needs adequate room for its large leaves and root system.

Allow approximately 45–60 cm between plants.

Crowded plants compete for light, nutrients and water and may develop smaller or less uniform sprouts.

Good spacing also improves airflow through the crop.

Where several rows are planted, allow approximately 75–100 cm between rows depending on the garden or production system.

Watering

Consistent moisture is important throughout the growing season.

Brussels sprouts develop a large leaf canopy before producing their crop, and this foliage requires reliable water.

The most important stages for watering include:

• Seed germination
• Seedling establishment
• Immediately after transplanting
• Rapid vegetative growth
• Sprout initiation
• Sprout enlargement

Water deeply enough to moisten the active root zone.

Mulching around established plants can help reduce evaporation, moderate soil temperature and suppress weeds.

Avoid keeping the soil permanently waterlogged, as Brussels sprouts require oxygen around the root system.

Feeding Brussels Sprouts

Brussels sprouts are relatively heavy-feeding vegetables because they remain in the ground for a long period and must develop substantial stems and foliage before producing their sprouts.

Begin with fertile, well-prepared soil.

A balanced vegetable fertiliser may be applied according to soil fertility and product directions.

Nitrogen is important during early vegetative development, but excessive late nitrogen can encourage continued leafy growth rather than firm sprout development.

The objective is steady, uninterrupted growth rather than repeated cycles of nutrient stress followed by excessive feeding.

Supporting the Plants

Long Island Improved is comparatively compact, but mature Brussels sprout plants can still become top-heavy.

Plants grown in exposed or windy locations may benefit from additional support.

Firm planting at transplanting time helps establish a stable root system.

Where necessary, mound a small amount of soil around the base of established plants or use a stake to prevent plants from rocking excessively in strong winds.

Avoid damaging the roots when inserting stakes beside mature plants.

How Brussels Sprouts Form

The edible Brussels sprouts are enlarged axillary buds.

They develop where each leaf joins the central stem.

The first sprouts usually begin enlarging near the base of the plant. As the season progresses, sprouts further up the stem develop and mature.

This explains why Brussels sprouts are traditionally harvested from the bottom of the stalk upwards.

A healthy Long Island Improved plant can carry numerous sprouts at different stages of development simultaneously.

Removing Lower Leaves

As the lower sprouts begin to enlarge, older yellowing leaves near the bottom of the plant may be removed.

This can make harvesting easier and improve airflow around the lower stalk.

Remove only leaves that are no longer contributing significantly to the plant or that obstruct mature sprouts.

Avoid stripping large numbers of healthy leaves unnecessarily. The plant still requires its foliage for photosynthesis and continued sprout development.

Topping Brussels Sprout Plants

Some growers remove the growing tip near the end of the season to encourage the remaining sprouts to enlarge more uniformly.

This practice is known as topping.

It should only be done once the plant has developed a substantial stalk of sprouts and sufficient time remains for those sprouts to finish.

Do not top young plants prematurely, as this stops further upward development of the main stem.

For home gardens with a long harvesting season, topping is optional rather than essential.

Common Brussels Sprout Pests

Like other brassicas, Brussels sprouts can attract several common garden pests.

These may include:

• Cabbage white butterfly caterpillars
• Cabbage moth caterpillars
• Aphids
• Slugs and snails
• Flea beetles
• Other brassica-feeding insects

Inspect plants regularly, particularly the undersides of leaves and the developing sprouts.

Fine insect netting can provide useful physical protection where cabbage butterflies and moths are persistent.

Ensure netting is secured around the edges so insects cannot enter underneath.

Follow locally appropriate integrated pest-management practices where treatment is required.

Crop Rotation

Long Island Improved belongs to the Brassicaceae family alongside cabbage, broccoli, cauliflower, kale, kohlrabi, turnips and many Asian greens.

Avoid repeatedly planting brassicas in exactly the same garden bed.

Rotating crops can help reduce the accumulation of some soil-borne pests and diseases and provides an opportunity to vary nutrient demands.

Where practical, use a multi-year rotation between brassica crops.

Crop rotation is particularly important where clubroot or other persistent brassica diseases have previously occurred.

Harvest

Long Island Improved generally requires approximately 90–120 days to reach useful maturity, although published maturity figures vary depending on whether they are measured from sowing or transplanting and according to growing conditions.

Begin harvesting when the lowest sprouts are firm, compact and approximately 2.5–3.5 cm across.

Do not wait for every sprout on the plant to reach full size simultaneously.

Harvest from the bottom upwards.

To remove an individual sprout, hold it firmly and twist or snap it away from the stalk. A small knife can also be used.

Continue harvesting progressively as the sprouts further up the stem become firm.

Remove any yellowing lower leaves as harvesting progresses if necessary.

Sprouts that become loose, open or excessively large may decline in eating quality, so pick them while the heads remain compact.

How to Tell When Brussels Sprouts Are Ready

A mature Brussels sprout should feel:

• Firm
• Dense
• Compact
• Tightly closed
• Approximately 2.5–3.5 cm across for this variety

Loose, leafy sprouts may indicate that the plant has experienced excessive heat, uneven growing conditions or that the sprout has remained on the stalk beyond its best harvest stage.

The lower sprouts normally provide the first indication that harvest is beginning.

Harvesting the Whole Stalk

Individual sprouts can be harvested progressively, but the entire stalk may also be harvested once a substantial proportion of the sprouts has reached usable size.

Cut the stalk near ground level with a strong knife or secateurs.

Remove the leaves if necessary.

Whole stalk harvesting can be convenient when a large quantity of sprouts is required at one time or at the end of the growing season.

For home gardeners, progressive picking generally provides a longer supply.

Using Long Island Improved Brussels Sprouts

Long Island Improved has the characteristic savoury flavour of a traditional Brussels sprout.

The harvested sprouts are suitable for:

• Oven roasting
• Steaming
• Boiling
• Sautéing
• Pan frying
• Stir-fries
• Gratins and baked vegetable dishes
• Soups and winter vegetable dishes
• Shredding for salads and slaws
• Freezing for later use

Avoid prolonged overcooking if you prefer a firmer texture and milder flavour.

Roasting at high heat is particularly popular because the outer leaves caramelise while the interior becomes tender.

Preparing Brussels Sprouts

Remove any damaged or yellow outer leaves.

Trim the very base of the stem without cutting so deeply that the sprout falls apart.

Rinse thoroughly in clean water.

Small sprouts may be cooked whole.

Larger sprouts can be halved through the stem to produce more even cooking and a larger surface for browning when roasting or sautéing.

For shredded preparations, slice the cleaned sprouts finely across the head.

Freezing Brussels Sprouts

Long Island Improved is suitable for freezing.

Select fresh, firm sprouts and remove damaged outer leaves.

Wash and sort the sprouts according to size.

Blanch using an appropriate recognised food-preservation method, then cool rapidly in iced water.

Drain thoroughly before packing into freezer-safe containers or bags.

Label with the variety and freezing date.

Correct blanching helps preserve colour, texture and quality during frozen storage.

Storing Fresh Brussels Sprouts

Fresh Brussels sprouts are best used soon after harvest.

If they cannot be used immediately, refrigerate promptly.

Avoid removing excessive outer leaves before storage, as the intact sprouts generally retain quality better.

Do not wash until shortly before use unless necessary, because excess surface moisture can accelerate deterioration during storage.

For longer storage, freezing is a practical option.

Open-Pollinated and Heirloom Variety

Long Island Improved is an open-pollinated variety rather than an F1 hybrid.

This means seed may be saved from properly grown plants if appropriate isolation and seed-production techniques are used.

However, Brussels sprouts readily cross-pollinate with compatible forms of Brassica oleracea, including many cabbages, broccoli, cauliflower, kale and kohlrabi.

Maintaining varietal purity therefore requires considerable isolation during flowering.

Brussels sprouts are also biennial seed producers. Plants normally require exposure to cool conditions before flowering and producing seed in their second growth phase.

For ordinary vegetable production, the plants are harvested before this reproductive stage.

Long Island Improved vs Modern F1 Brussels Sprouts

Modern F1 Brussels sprout hybrids are often bred for highly uniform maturity, concentrated harvest, disease resistance and commercial production characteristics.

Long Island Improved represents an older style of Brussels sprout.

Its advantages include:

• Open-pollinated genetics
• Heirloom history
• Traditional flavour
• Progressive harvest
• Suitability for home vegetable gardens
• Potential for seed saving under appropriate isolation

Because it is open-pollinated, individual plants and sprouts may show somewhat more natural variation than a highly uniform F1 hybrid.

Perfect For

• Home vegetable gardens
• Heirloom vegetable gardens
• Cool-season vegetable production
• Autumn and winter gardens
• Traditional open-pollinated varieties
• Raised garden beds
• Market gardens
• Progressive harvesting
• Fresh Brussels sprouts
• Roasting and baking
• Steaming and sautéing
• Winter vegetable dishes
• Freezing
• Seed-saving gardeners with appropriate isolation

Frequently Asked Questions

What are Long Island Improved Brussels sprouts?

Long Island Improved is a traditional open-pollinated Brussels sprout variety dating to the late 19th century. It produces numerous compact green sprouts along a relatively short, sturdy central stalk.

Is Long Island Improved an heirloom variety?

Yes. Long Island Improved is widely regarded as an heirloom Brussels sprout variety and has been grown since the 1890s.

Is Long Island Improved an F1 hybrid?

No. Long Island Improved is an open-pollinated variety rather than an F1 hybrid.

What is the botanical name of Brussels sprouts?

Brussels sprouts belong to Brassica oleracea and are commonly classified botanically as Brassica oleracea var. gemmifera.

How tall does Long Island Improved grow?

Long Island Improved is a relatively compact Brussels sprout and commonly reaches approximately 45–60 cm under typical garden conditions. Plant size varies with climate, fertility and spacing.

How large are Long Island Improved Brussels sprouts?

The variety typically produces small to medium sprouts approximately 2.5–3.5 cm in diameter.

What colour are Long Island Improved Brussels sprouts?

The sprouts are medium to dark green.

How long does Long Island Improved take to mature?

Allow approximately 90–120 days depending on climate, sowing method and whether maturity is measured from sowing or transplanting. Brussels sprouts are a long-season crop and should be timed so sprout development occurs during cool weather.

When should I sow Brussels sprouts in Australia?

Timing depends strongly on climate. In cool regions they may be sown from spring into summer. Temperate gardeners commonly sow from summer into autumn, while subtropical growers should generally concentrate on late-summer to autumn sowings for winter production.

Can Brussels sprouts grow in Queensland?

Yes, particularly in cooler parts of Queensland and during the coolest months. In subtropical areas, sow in late summer or autumn so the crop develops through autumn and winter. Hot tropical lowland conditions are considerably more challenging.

Can Brussels sprouts grow in Brisbane?

Yes, but timing is important. In Brisbane’s subtropical climate, establish the crop from late summer through autumn so the sprouts mature during the cooler winter period rather than during hot weather.

Can Long Island Improved tolerate frost?

Established Brussels sprout plants tolerate light frost and cool conditions well. Cool weather can also improve eating quality. Young seedlings should nevertheless be protected from severe conditions while establishing.

Do Brussels sprouts taste better after cold weather?

Cool conditions are generally associated with sweeter, better-quality Brussels sprouts. This is one reason the crop is traditionally grown to mature in autumn and winter.

Do Brussels sprouts need full sun?

Yes. Choose a position receiving full sun for strong plant growth and reliable sprout development.

What soil is best for Brussels sprouts?

Use fertile, moisture-retentive but well-drained soil with good organic matter. A slightly acidic to near-neutral pH is generally suitable.

Should I start Brussels sprouts in trays?

Starting seed in trays or punnets is usually an excellent approach. It allows young seedlings to be protected from pests and makes it easier to transplant strong plants at the correct spacing.

Can Brussels sprouts be direct sown?

Yes. Direct sowing is possible in suitable cool conditions, although raising seedlings in trays often provides more reliable establishment.

How deep should Brussels sprout seeds be planted?

Sow approximately 5–10 mm deep and keep the growing medium evenly moist until germination.

How long do Brussels sprout seeds take to germinate?

Seeds commonly germinate in approximately 5–10 days under suitable moisture and temperature conditions.

What temperature do Brussels sprout seeds need to germinate?

Brussels sprout seed germinates across a relatively broad temperature range. Moderate temperatures around 15–24°C generally provide reliable establishment, although germination can occur outside this range.

When should Brussels sprout seedlings be transplanted?

Transplant when seedlings are sturdy, have developed several true leaves and are generally around 4–6 weeks old.

How far apart should Long Island Improved Brussels sprouts be planted?

Allow approximately 45–60 cm between plants and around 75–100 cm between rows.

Why do Brussels sprouts need so much space?

Each plant develops a large leaf canopy, substantial root system and strong central stalk. Adequate spacing reduces competition and improves airflow and sprout development.

How often should Brussels sprouts be watered?

Water according to soil and weather conditions rather than a fixed schedule. The goal is consistent moisture without waterlogging, particularly during rapid growth and sprout development.

Are Brussels sprouts heavy feeders?

They have relatively high nutrient requirements because they remain in the garden for a long period and produce substantial vegetative growth before forming sprouts.

Why are my Brussels sprouts loose?

Loose sprouts can result from excessive heat, uneven growth, excessive nitrogen, unsuitable planting time or sprouts remaining on the plant beyond their best stage.

Why aren’t my Brussels sprouts forming?

Common causes include planting at the wrong time, prolonged warm conditions, insufficient plant maturity, poor fertility, overcrowding or severe growing stress.

Where do Brussels sprouts grow on the plant?

The sprouts form in the leaf axils along the central stem, where each leaf joins the stalk.

Which Brussels sprouts should I harvest first?

Harvest the lowest sprouts first. They mature before those higher on the stalk.

How do I know when Brussels sprouts are ready?

Pick when the sprouts are firm, tightly closed and approximately 2.5–3.5 cm across. Avoid waiting until the heads become loose and leafy.

How do I harvest Brussels sprouts?

Twist or snap mature sprouts away from the central stalk, beginning at the bottom and working upwards as additional sprouts reach harvest size.

Can I harvest the whole Brussels sprout stalk?

Yes. The entire stalk can be cut when a substantial proportion of sprouts has matured, although progressive picking generally extends the home harvest.

Should I remove Brussels sprout leaves?

Older yellowing lower leaves can be removed as sprouts mature. Avoid unnecessarily removing healthy upper foliage, as the leaves continue supplying energy to the developing crop.

Should I top Brussels sprout plants?

Topping is optional. Removing the growing tip late in the season can encourage existing sprouts to finish more uniformly, but it should not be done while plants are still developing their main stalk.

Can Brussels sprouts be grown in pots?

They can be grown in very large containers, but they are generally better suited to garden beds because each plant requires substantial root space, fertility, moisture and physical support.

Can Long Island Improved Brussels sprouts be frozen?

Yes. The variety is suitable for freezing. Clean and blanch the sprouts using an appropriate food-preservation method before freezing.

Can Brussels sprouts be roasted?

Yes. Roasting is an excellent preparation method. Halved sprouts develop browned, caramelised surfaces while retaining a tender centre.

Can Brussels sprouts be eaten raw?

Yes. Fresh sprouts can be finely shredded and used raw in salads and slaws. Wash them thoroughly and remove damaged outer leaves before preparation.

Can I save seed from Long Island Improved?

Yes, because Long Island Improved is open-pollinated. However, Brussels sprouts cross readily with compatible Brassica oleracea crops, so substantial isolation and appropriate seed-saving techniques are required to maintain varietal purity.

Will Brussels sprouts cross with cabbage or broccoli?

Yes. Brussels sprouts, many cabbages, broccoli, cauliflower, kale and kohlrabi belong to the same species and can cross-pollinate when flowering simultaneously.

Are Brussels sprouts annual or biennial?

Brussels sprouts are botanically biennial. For vegetable production they are normally grown as an annual crop and harvested before flowering.

What pests attack Brussels sprouts?

Common pests include cabbage white butterfly caterpillars, cabbage moth larvae, aphids, slugs and snails. Regular inspection and fine insect netting can help protect the crop.

Can I cover Brussels sprouts with insect netting?

Yes. Fine insect netting is particularly useful for excluding cabbage butterflies and moths. Secure the edges carefully to prevent adult insects entering beneath the cover.

Should Brussels sprouts be crop rotated?

Yes. Avoid repeatedly growing Brussels sprouts or other brassicas in the same bed. Crop rotation can help reduce pest and disease pressure and improve long-term soil management.

Is Long Island Improved suitable for home gardens?

Yes. Its comparatively compact habit, progressive harvest and traditional flavour make Long Island Improved particularly well suited to home vegetable gardens.

Is Long Island Improved suitable for market gardens?

Yes. It can be grown by market gardeners seeking a traditional open-pollinated Brussels sprout, although modern F1 hybrids may offer greater uniformity for intensive commercial production.

What is the difference between Long Island Improved and modern hybrid Brussels sprouts?

Long Island Improved is an older open-pollinated variety with traditional flavour and some natural plant-to-plant variation. Modern F1 varieties are often bred for greater uniformity, concentrated maturity and particular commercial production characteristics.

Why is Long Island Improved still popular?

Its combination of heirloom history, dependable production, compact plants, firm green sprouts and traditional eating quality has kept Long Island Improved popular with home gardeners for well over a century.