How to Germinate Caper Seeds: A Step-by-Step Guide

Looking to grow your own caper plants from seed? Caper seeds (Capparis spinosa) can be tricky to germinate, but with the right steps and a little patience, you’ll be rewarded with a hardy, drought-tolerant shrub that thrives in New Zealand’s hot, dry summers.

Whether you're a beginner or experienced gardener, here’s our proven method for caper seed germination—including tips on stratification, scarification, gibberellic acid, and more.

Read more about the different techniques, their purpose, and why we use them in the Difficult to Germinate Seed Guide. 

🥶 Step 1: Cold Stratify the Seeds (4–10 Weeks)

• Soak seeds in warm water for 12–24 hours.
• Place them in moist sand, or use the damp paper towel method (sealed in a plastic bag or container), but watch for mold growth!
• Refrigerate for 4 to 10 weeks — we recommend 6 weeks.
• Label with the date so you don’t forget!

This process simulates winter, softens the seed coat, and primes the seeds to germinate when sown.

💦 Step 2: Soak Again Before Planting

After stratification, soak the seeds again in warm (not boiling) water for 12–24 hours. This helps rehydrate the seed and signals the start of the growing season.

🪵 Step 3: Scarify the Seed Husk

Caper seeds have a tough outer shell. Lightly scratch or sand the seed coat with sandpaper or a nail file — just enough to dull the surface, not damage the seed inside. If you see white, you've gone too far.

This step helps improve water uptake and increases your germination success.

🌿 Optional: Use Gibberellic Acid (GA₃)

For even better results, soak the seeds in a diluted solution of gibberellic acid (GA₃) before planting. GA₃ can stimulate seed hormones and help stubborn seeds sprout faster.

🪴 Step 4: Planting the Seeds

Plant your seeds in small pots using a free-draining cactus or succulent mix. Try our Succulent and Cacti Mix.

A 50/25/25 mix of potting soil, sand, and perlite

• Plant seeds about 1 cm deep.
• Use a seed tray, cell tray, or small pots (5–7 cm).
• Keep the soil evenly moist but not soggy.

TIP: Use a heat mat to maintain a soil temperature of 21–29 °C (70–85 °F). Warmth dramatically improves germination rates and is required in most cases.

TIP2: Cover with vermiculite, helps retain even moisture.

⏳ Step 5: Be Patient – Germination Takes Time

Caper seeds may take anywhere from 3 weeks to 2 years to germinate.

• ✅ Keep soil moist and warm
• ✅ Watch for waterlogging and mold growth
• ✅ Don’t give up too early — staggered germination is common

🌱 Aftercare: Transplanting Seedlings

• Transplant when seedlings are 7–10 cm tall and have multiple leaves.
• Use the same free-draining soil mix.
• Gradually harden them off before planting outdoors.
• Keep in a sunny, sheltered location. Capers love full sun and heat.
• Protect from frost.

☀️ Growing Capers in New Zealand

Caper bushes thrive in dry, rocky soils and can tolerate drought once established. They’re ideal for:

• Rock gardens
• Raised beds
• Coastal climates
• Sunny patios and containers

They’re great in hot, dry areas but will need protection from frost, especially in their first year.

Capers are frost tender.

✨ Quick Recap: Caper Seed Germination Steps

1. Cold stratify in fridge for 4–10 weeks
2. Soak seeds in warm water overnight
3. Lightly scarify with sandpaper
4. (Optional) Soak in gibberellic acid solution
5. Sow in cactus mix, 1 cm deep
6. Keep warm and moist (21–29 °C)
7. Germination: 3 weeks - 2 years
8. Transplant when 7–10 cm tall

🧠 Did You Know?

Capers are actually flower buds! If left to bloom, the plant produces beautiful pinkish-white flowers with long, dramatic stamens.

💬 Have Questions?

Reach out to us anytime via our Contact Page.