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1 October 2020

No-grow bird seed

Feed the birds without spilled seed germinating and becoming weeds in your garden with these no-grow bird seeds.
Filling-bird-feeder 2
JH
Jade Harding

Feeding garden birds is an enjoyable pastime for many, but one drawback can be that spilled bird seed begins to grow and create a blanket of weeds below your feeder.

To combat this, many companies now supply seed mixes labelled as ‘no grow’ or ‘no mess’. These contain oats and sometimes suet pellets along with various seeds, such as sunflower and maize, that have been kibbled – cracked, chopped or ground – or heat treated to inhibit germination.

Find out if these treatments actually work in our results table below.

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Best no-grow bird seeds

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No-grow bird seed Germination four days after sowing Germination 10 days after sowing % tray coverage Outside germination Overall rating
96%

With the best score in the test, this mix of oats, maize, sunflower, peanuts, barley and wheat produced just three grass-like seedlings in the greenhouse, which grew into fairly weak plants. These were probably oats, but as they didn’t get to flowering size, we can’t be sure. Outside, just a single maize seedling grew. A big bonus is this blend doesn’t include suet pellets, which can turn slimy and encourage mould growth if left.

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No-grow bird seed Germination four days after sowing Germination 10 days after sowing % tray coverage Outside germination Overall rating
92%

Containing a blend of oats, kibbled maize, kibbled sunflower hearts and peanuts, plus suet pellets and petrified wheat (cooked to make it more easily digested), this produced only a handful of sunflower seedlings in our greenhouse seed trays. Outside in our fruit cage, nothing germinated at all and the seed soon disappeared, most likely eaten by mice.

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No-grow bird seed Germination four days after sowing Germination 10 days after sowing % tray coverage Outside germination Overall rating
84%

Our third Best Buy contains similar ingredients to the other two – sunflower hearts, flaked maize, suet and naked oats – and although it grew a few sunflowers and a couple of oat seedlings in the greenhouse, germination outdoors was non existent, with no seeds visible after a few days. The most likely reason for this is that the seeds were eaten by mice before they had a chance to get going.

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No-grow bird seed Germination four days after sowing Germination 10 days after sowing % tray coverage Outside germination Overall rating
76%

Our greenhouse-sown seeds produced some sunflower and millet plants, while outside very few seeds germinated and the remainder were most likely eaten by mice 

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No-grow bird seed Germination four days after sowing Germination 10 days after sowing % tray coverage Outside germination Overall rating
68%

Indoor-sown seeds produced sunflowers, some grass-like seedlings and a brassica of some kind; outside seeds gave us some sunflowers.

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No-grow bird seed Germination four days after sowing Germination 10 days after sowing % tray coverage Outside germination Overall rating
64%

Seeds in the greenhouse grew into a mass of tough-looking grass-like plants, but outdoor seeds quickly disappeared so were probably eaten by mice.

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No-grow bird seed Germination four days after sowing Germination 10 days after sowing % tray coverage Outside germination Overall rating
40%

This contained a high proportion of whole sunflower seeds and millet, most of which germinated and rapidly covered the seed tray. When allowed to grow on, this gave us a tray full of millet plants, which all flowered and set seed, interspersed with sunflowers, all of which produced flower heads. Outside, germination wasn’t so pronounced, but we still grew a good number of millet plants.

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No-grow bird seed Germination four days after sowing Germination 10 days after sowing % tray coverage Outside germination Overall rating
36%

As well as the ingredients listed on the packet, this mix contained millet, red dari (sorghum) and small round black seeds. In the greenhouse, more than half of the seed tray was covered, largely by millet plants. The small round seeds turned out to be a brassica, which grew so well outside that it outcompeted the weeds, covering the patch, but also allowing some space for several millet plants.

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Table notes

1 star = 80-100% germination; 2 stars = 60-80% germination; 3 stars = 40-60% germination; 4 stars = 20-40% germination; 5 stars = 0-20% germination. Rating ignores price and is based on: germination after four days 20%; germination after 10 days 20%; tray coverage 20%; outside germination 40%. Prices correct as of 2020.

Why Which? no-grow bird seed reviews are better

Which? is independent and doesn't accept advertising or freebies, so you can trust our reviews to give you the full, honest and impartial truth about a product.

We tested eight well-known brands, both on seed trays in the greenhouse and outdoors.

Each mix was sown in a seed tray of Best Buy compost and kept in the greenhouse.

We also sowed each mix on the ground outside in a bed protected by a fruit cage.

  • We recorded germination in the greenhouse four days and 10 days after sowing.
  • We recorded germination after 10 days on the seeds placed outside.
  • Any seed that germinated was allowed to grow on so we could see whether the resulting plants were invasive or could be problematic.

We also contacted the manufacturers to find out the exact ingredients of each seed blend, since we noticed that some contained a greater variety of seeds than was listed on the packaging.

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