Aptus - P-Boost

A phosphorus booster with organic nitrogen and L-amino acids. 30 to 50 ml per 100 litres, from bud formation to the sixth week of bloom.

A booster you can also use as a pH-down

This is the property missing from most pages about this product. Aptus write it themselves: P-Boost has acidifying properties and can be used to lower the pH of the water in your tank.

That is not a side effect but a use, and it changes the order you work in. Add P-Boost after setting your pH and your reading no longer holds. Add it before the correction and it does part of the work, so you use less pH-down.

In practice: mix your feed and your boosters, then measure, then correct what is left. At a phosphorus feed of this size that makes a noticeable difference to how much acid you need.

What the phosphorus is for

Aptus set the action out more broadly than flower formation alone. P-Boost stimulates the production of hormones, vitamins and proteins in the plant, stimulates bud and fruit formation and bud development, and improves photosynthesis.

The first of those is the interesting one. Phosphorus sits in ATP, the energy carrier the plant pays for almost every process with, and in the building blocks of DNA. So a phosphorus feed in bloom is not only about bigger flowers but about the energy the plant makes them with.

What else is in it

Alongside high concentrations of phosphorus, P-Boost contains organic nitrogen and L-amino acids. The nutrients are organically chelated with those amino acids, which according to Aptus gives high bioavailability.

Note that this means there is nitrogen in it. In late bloom you usually want to be winding nitrogen down, and that is one reason this product's window stops at week six rather than running to harvest.

The window, and a dose that moves with it

Use P-Boost from bud formation through the sixth week of bloom, at 30 to 50 ml per 100 litres of water.

Aptus add a tip you can see reflected in their schedule: raise the dose over the course of the cycle for a better result. So you start at the bottom of the range and work upward rather than feeding the same amount throughout.

After week six, K-Boost takes over as the ripening stimulator. The two overlap briefly and do different jobs.

In use

Shake well before use. Mix 30 to 50 ml per 100 litres of water, that is 3 to 5 ml in 10 litres.

Fully water-soluble and it leaves no residue in the irrigation system, so it suits drippers. Measure your pH after adding it, for the reason above.

Available sizes

Technical Specifications:

• Type: organo-mineral phosphorus booster
• Manufacturer: Aptus
• Contains: high concentrations of phosphorus (P), organic nitrogen (N), L-amino acids
• Dosage: 30 to 50 ml per 100 litres, rising through the cycle
• Period: from bud formation to the sixth week of bloom
• pH: acidifying, usable to lower the pH of the tank
• Solubility: fully water-soluble, leaves no residue
• Successor: K-Boost, from week five of bloom
• Before use: shake well

Frequently asked questions

Does this lower my pH?
Yes. Aptus state that P-Boost has acidifying properties and that you can use it to lower the pH in the tank. So measure after adding it.

When do I stop?
After the sixth week of bloom. There is nitrogen in it too, and you do not want to keep topping that up in late bloom.

Should the dose climb?
Aptus advise it: start at the bottom of the 30 to 50 ml range and work up through the cycle.

Can I use it in a drip system?
Yes, it is fully water-soluble and leaves no residue.

How does it differ from K-Boost?
P-Boost works on bud and fruit formation and runs to week six. K-Boost is a ripening stimulator for the final weeks.