Osmocote alternative

What it costs

Why the two charts differ. Osmocote is concentrated and goes on once, so a season costs less per square metre. Ours puts 300 g of organic matter and minerals on each square metre over the season, against 50 g of coated prills.

Osmocote Exact PrePlant 5 to 6 month (17-9-10 with magnesium and trace elements): rate from the supplier's directions for closely planted areas; 1 kg packs at £9.00 to £10.80 from two UK suppliers, checked 14 Nov 2026. Dr Forest from £12.00 (1.5 kg), £24.50 (4 kg) and £46.00 (9 kg) bags. Osmocote is a trademark of its owner; Dr Forest is not affiliated.

What the coating leaves behind

Every Osmocote prill is fertiliser sealed inside a synthetic polymer resin, the same family of materials as plastics. The coating is what gives it six months: nutrients seep out through it as the soil warms. When the feed has gone, the empty shell is what is left in your soil. Its maker says the resin then breaks down and disintegrates, and gives no timescale.

• The law is catching up. EU fertiliser rules now require the polymers that coat controlled-release fertilisers to be biodegradable, and Osmocote's maker has developed a new biodegradable coating in response.
• Coated fertilisers shed microplastics. On Japanese coastlines, spent fertiliser capsules were about 90% of the microplastics collected in the irrigation season (Katsumi et al., 2020). That study was of polyethylene-coated rice fertilisers, not Osmocote.
• Ours has no coating. Soil life does the slow release, by breaking the ingredients down. Nothing in the bag is there to hold the feed back.

1. Regulation (EU) 2019/1009 on fertilising products, Annex II, CMC 9: polymers.
2. Katsumi N, Kusube T, Nagao S, Okochi H (2020). The role of coated fertilizer used in paddy fields as a source of microplastics in the marine environment. Marine Pollution Bulletin 161, 111727.

What the extra buys you

Osmocote costs less per season. This is what you get for the difference.

• Soil that gets better every year. Most of the bag is carbon-rich organic matter that feeds soil life and builds structure. Osmocote is coated mineral fertiliser with no organic matter, so your soil ends the season no better than it started.
• Calcium and sulphur built in. Gypsum, kieserite and bone meal supply them, alongside magnesium. Osmocote Exact PrePlant declares magnesium and trace elements, but no calcium.
• Every ingredient named. Ten organic inputs, each one on the label, from alfalfa meal to fermented biochar.
• No coating. Every ingredient is a plant meal, a mineral or a soil conditioner. Osmocote's nutrients sit inside a synthetic polymer resin.
• Feeding you can adjust. Three applications let you match the feed to the crop as the season goes. One application of Osmocote is set for the next six months.
• Small batches, compostable bag. Formulated and blended in Stockport.

Side by side

Osmocote analysis, longevity and directions from UK supplier listings for Osmocote Exact PrePlant 5 to 6 month, checked 14 Nov 2026. Other Osmocote grades differ.

How to switch

Swap the once-a-season prills for a feed the soil can use. Start in spring as growth begins:

A handful is 40 to 50 g; a level tablespoon is 12 to 15 g. Water in every time.

Need help with a particular plant? Our How to Grow Plants guides cover 194 plants, from sowing to harvest.

When Osmocote makes sense

• You want to feed once and forget it for the season.
• You want the lowest cost per square metre. Osmocote wins that.
• You grow in hanging baskets and tight containers where there is no room to top-dress.
• You want a feed with no animal ingredients. Ours contains bone meal.

Common questions

What is the closest Dr Forest match to Osmocote?

Dr Forest All Purpose 4-4-4. Both are slow-feeding granules for beds, borders, shrubs and pots. The NPK numbers look very different because the two contain different things. Osmocote's 17-9-10 is concentrated mineral fertiliser inside a polymer resin coat, with no organic matter, so it feeds the plant but does nothing for the soil. Most of a bag of All Purpose 4-4-4 is organic matter: carbon-rich plant meals, seaweed and biochar, with the nutrients held in that material alongside calcium, magnesium and sulphur. Soil life breaks it down and releases the nutrients over weeks, and the carbon left behind builds the soil.

Is Dr Forest cheaper than Osmocote?

By the kilo, yes: £5.11 to £8.00 for Dr Forest All Purpose 4-4-4 against £9.00 to £10.80 for Osmocote Exact PrePlant (prices checked 14 Nov 2026). Per square metre for a season, no: one 50 g application of Osmocote costs 45p to 54p, against £1.53 to £2.40 for three 100 g applications of Dr Forest.

Is Osmocote coated in plastic?

Osmocote prills are coated in a synthetic polymer resin, the same family of materials as plastics. The coating is what controls the release. Its maker describes it as an organic resin that breaks down after the nutrients are released. EU rules now require the coatings on controlled-release fertilisers to be biodegradable. Dr Forest All Purpose 4-4-4 has no coating.

Is Osmocote organic?

No. Osmocote is a mineral fertiliser in a synthetic polymer resin coat. Dr Forest All Purpose 4-4-4 is blended from ten organic ingredients, including alfalfa meal, bone meal, seaweed and gypsum, and the alfalfa meal and flaxseed meal are certified organic.

What is Osmocote fertiliser good for?

Feeding container plants, shrubs, trees and planted beds for a whole season from one application. The coating lets nutrients out gradually as the soil warms, so the grade described here lasts 5 to 6 months.

Can I just sprinkle Osmocote on top of soil?

The directions say to work it carefully into the topsoil and water it in thoroughly, or to add it to the planting hole. Dr Forest All Purpose 4-4-4 is used the same way on beds: worked into the top 5 to 10 cm and watered in. In pots it can be scattered on top.

Is Osmocote the same as Miracle-Gro?

No. Miracle-Gro All Purpose is a soluble feed you mix into the watering can every two weeks. Osmocote is a coated granule that releases over months. Both are mineral feeds with no organic matter.

Can I use Osmocote and Dr Forest All Purpose together?

Yes, but not both at full rate on the same bed. If Osmocote is already down, let it run its course, then move to All Purpose 4-4-4 next spring.

More: all brand alternatives · Miracle-Gro All Purpose · Vitax Q4 · Phostrogen Organic

Written by Joe Barrington, Dr Forest, Stockport. Osmocote and Dr Forest prices and rates checked 14 Nov 2026.