At Seedmart, we want to be transparent about the seeds we sell. Our preference is always untreated seed. However, Australian laws and biosecurity rules sometimes require us to supply treated seed. In this article, we explain why, which varieties are affected, and how we continue to work towards more untreated options while keeping quality high.
Australia’s Biosecurity and Seed Quality
Australia has a pristine environment, and we work hard to protect it. Our country runs one of the strictest biosecurity systems in the world. These rules keep our ecosystems safe and support our reputation for producing world-leading agricultural goods. They also ensure that you, the grower, receive seed that is clean, high quality, and pure.
Australia sets nil tolerance for many weed seeds and allows only minimal levels of a few safe species. This protects both growers and consumers. You can read more on the Department of Agriculture’s official site: Seeds for Sowing Contaminants Tolerance.
If you have passed through customs at an Australian airport, you know how strict these rules are—fines apply even for small breaches. Strict laws also exist inside Australia. For example, WA, QLD, and TAS enforce tomato control orders.
What Are Treated Seeds?
Treated seeds carry a light coating. Suppliers apply this coating to protect against soil diseases and fungal attacks. Most treatments use a mild fungicide such as thiram. The coating works during germination when seedlings are vulnerable. Once plants establish, they grow without it.
Think of the coating as a raincoat. It protects the seedling at the start. After that, the plant grows on its own strength. As a result, growers enjoy stronger germination and more reliable crops.
- Purpose: Protect seedlings at germination.
- Method: A thin layer on the seed coat.
- Result: More seedlings sprout and survive.
Why Import Seeds?
We always aim to supply Australian grown seeds, and we work hard with local growers to guarantee supply. However, Australia’s seed market is small, and local production cannot supply every variety in bulk. Because of this, we sometimes import seed. We do so for three reasons:
- Missing varieties: Some crops, especially Asian greens, are not available in bulk within Australia.
- Supply shortages: Weather or crop loss can reduce local stock for months.
- Better value: Bulk imports keep prices fair for gardeners and farmers.
When we import certain varieties, the Department of Agriculture requires treatment with a broad-spectrum fungicide or insecticide. These rules protect farms and ecosystems from pests and diseases. As a result, treated seed remains the only legal option in some cases.
Which Seeds Are Treated?
The Australian Department of Agriculture requires mandatory treatment for a small number of imported seed varieties. See BICON (Australian Department of Agriculture website) for details. This list includes:
- Rocket (Eruca sativa)
- Mizuna (Brassica rapa)
- Pak Choi/Bok Choy (Brassica rapa subsp. chinensis)
- Turnip (Brassica rapa)
- Tatsoi (Brassica rapa var. rosularis)
- Radish (Raphanus sativus)
- Chinese Cabbage (Brassica rapa subsp. pekinensis)
- Honeydew & Rockmelon (Cucumis melo)
- Cucumber (Cucumis sativus)
In summary: All imported Eruca sativa, Brassica rapa and Raphanus sativus seeds require mandatory treatment.
We review this list each season. Whenever an untreated version becomes available in Australia, we switch immediately. In fact, we have already replaced several treated products in the past by doing exactly this.
Why Use Treated Seeds?
We prefer untreated seed, but treated seed does bring some benefits. For example, it:
- Meets the law: Treated imports comply with strict quarantine rules.
- Improves germination: Coated seeds sprout more evenly.
- Reduces waste: Stronger germination means fewer re-sows.
- Keeps supply stable: Lets us stock popular crops year-round.
On the other hand, untreated seed gives more choice to seed savers and organic growers. That is why we keep pushing for untreated supply whenever possible.
Our Transparency Promise
We always label treated seed clearly on our website and packaging. You never need to guess. We also explain why each seed is treated and how we plan to reduce them. This open approach helps you buy with confidence.
Every year we trial new lines and work with growers to expand local supply. As soon as a reliable untreated option appears, we switch to it. As a result, the number of treated lines continues to shrink each year.
Common Questions
Are treated seeds safe?
Yes. Suppliers apply coatings under strict quality control. Wash hands after handling seeds and avoid breathing in seed dust.
Do treated seeds create treated plants?
No. The coating only works at sprouting. Once seedlings grow, the treatment no longer affects them.
Does treatment change flavour?
No. Vegetables from treated seed taste the same as crops grown from untreated seed.
Can I save seed from treated plants?
You can, but results vary. Many treated lines are hybrids, so they do not produce stable seed. If you want to save seed, choose open-pollinated and untreated varieties instead.
Our Ongoing Work
Seedmart gives gardeners and farmers the widest choice of seed at the best quality. We sell only a small share of our range as treated seed, and we use it only when no untreated option exists. At the same time, we invest in trials, speak with growers, and build local partnerships. Thanks to this work, more lines return to untreated supply each season.
Our promise is simple: we deliver high-quality seed with strong germination, clear labelling, and honest information—always.
Key Points
- We prefer untreated, Australian-grown seed.
- We import only when local supply cannot meet demand.
- Some imported seed varieties must be treated under Australian law.
- Current treated lines include rocket, mizuna, pak choi, turnip, tatsoi, radish, Chinese cabbage, cucumber, honeydew, and rockmelon.
- We label treated seed clearly and replace it with untreated seed when possible.
- We always focus on high-quality, clean seed with strong purity.