FoxFarm Open Sesame 5-45-19 Early Flowering Fertiliser – 454g (1lb)

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£31.50

A concentrated 5-45-19 soluble fertiliser designed to support vigorous bud development as plants make the transition into flowering.

FoxFarm Open Sesame is an early flowering fertiliser formulated to deliver targeted nutrition when plants move from vegetative growth into bloom. Its high-phosphorus 5-45-19 analysis makes it particularly suited to the first signs of bud formation and the early to middle stages of the flowering cycle.

The soluble formula provides nitrogen, phosphorus and potassium alongside sulphur and chelated iron, manganese and zinc. It dissolves into water for straightforward root-zone application across hydroponic, soil and soilless growing systems.

Open Sesame can be used on its own or at a reduced concentration alongside other nutrients, giving growers flexibility when incorporating it into an established flowering feed programme.

Why choose FoxFarm Open Sesame?

  • Designed for early flowering – formulated specifically for the transition from vegetative growth into the early and middle weeks of bloom.
  • High-phosphorus 5-45-19 formula – delivers targeted flowering nutrition as bud development begins.
  • Supports vigorous flowering – provides concentrated nutrition during early bud development.
  • Water-soluble formula – mixes readily into water for root-zone feeding.
  • Flexible feeding options – suitable for stand-alone use or at a lower rate alongside other nutrients.
  • Suitable across growing systems – use with hydroponics, aeroponics, soil and soilless media.
  • Includes chelated micronutrients – supplies iron, manganese and zinc alongside its primary NPK nutrition.

What is FoxFarm Open Sesame used for?

Open Sesame is designed for the transition into flowering. FoxFarm recommends introducing it from the first signs of buds and continuing through the middle weeks of the flowering cycle.

Its 5-45-19 analysis places particular emphasis on phosphorus while also supplying potassium, nitrogen and selected micronutrients. This makes Open Sesame a stage-specific soluble fertiliser rather than a general-purpose feed for the entire crop cycle.

It can be used in hydroponic and aeroponic systems as well as containers, soil and soilless growing media.

How to use FoxFarm Open Sesame

For stand-alone hydroponic use, mix 6g per 4 litres of water in the reservoir. FoxFarm recommends flushing the system every two weeks.

For stand-alone soil use, mix 3 – 6g per 4 litres of water and feed once per week.

When combining Open Sesame with other nutrients, use 1.5 – 3g per 4 litres of water in hydroponic or soil applications. For soil-grown plants, apply once per week.

Always add Open Sesame to the final volume of fresh water and mix thoroughly. Do not mix concentrated soluble fertilisers together while dry. Open Sesame is intended for root-zone feeding and should not be applied as a foliar spray.

FoxFarm Open Sesame 454g product details

Product FoxFarm Open Sesame
Product type Early flowering soluble fertiliser
Size 1lb / 454g
Form Water-soluble powder
NPK 5-45-19
Total nitrogen (N) 5%
Available phosphate (P₂O₅) 45%
Soluble potash (K₂O) 19%
Sulphur (S) 2%
Iron (Fe) 0.15% chelated iron
Manganese (Mn) 0.05% chelated manganese
Zinc (Zn) 0.05% chelated zinc
Growth stage Early flowering through the middle weeks of bloom
Hydroponic rate – stand alone 6g per 4L
Soil rate – stand alone 3 – 6g per 4L
Rate with other nutrients 1.5 – 3g per 4L
Suitable growing methods Hydroponics, aeroponics, soil & soilless media
Foliar application No
Outer case quantity 12

FoxFarm Open Sesame FAQs

What is FoxFarm Open Sesame used for?

FoxFarm Open Sesame is a high-phosphorus soluble fertiliser designed for the transition from vegetative growth into early flowering. It supplies targeted nutrition to support vigorous flowering and bud development.

What is the NPK of FoxFarm Open Sesame?

Open Sesame has an NPK analysis of 5-45-19, providing 5% nitrogen, 45% available phosphate and 19% soluble potash.

When should I start using FoxFarm Open Sesame?

Start using Open Sesame from the first signs of buds and continue through the middle weeks of the flowering cycle. FoxFarm also suggests beginning at around the fifth or sixth week of a plant's life where appropriate.

How much FoxFarm Open Sesame should I use?

For stand-alone hydroponic feeding, use 6g per 4 litres of water. For stand-alone soil feeding, use 3 – 6g per 4 litres. When combining Open Sesame with other nutrients, reduce the rate to 1.5 – 3g per 4 litres.

Can FoxFarm Open Sesame be used in hydroponics?

Yes. Open Sesame is suitable for hydroponic systems. The stand-alone hydroponic application rate is 6g per 4 litres of reservoir water.

Can Open Sesame be used in soil?

Yes. Open Sesame is suitable for soil-grown plants. For stand-alone feeding, use 3 – 6g per 4 litres of water and apply once per week.

Can FoxFarm Open Sesame be mixed with other nutrients?

Yes. Open Sesame can form part of a wider nutrient programme. When combined with other nutrients, FoxFarm recommends reducing the application rate to 1.5 – 3g per 4 litres of water.

Can Open Sesame be used as a foliar spray?

No. FoxFarm specifies that Open Sesame should not be used as a foliar spray. It is designed for application through the root zone.

What comes after Open Sesame in the FoxFarm feeding schedule?

Open Sesame is the early flowering product in FoxFarm's soluble fertiliser programme. Beastie Bloomz follows for the middle flowering stage, before moving to Cha Ching for late flowering.

How long will a 454g tub of FoxFarm Open Sesame last?

At the full stand-alone hydroponic rate of 6g per 4 litres, a 454g tub is sufficient to prepare approximately 300 litres of nutrient solution. At the lower combined-nutrient rates, the same tub will treat considerably more.

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£31.50