Players are able to boost up to +5 with the herblore skill. Other than a few exceptions, boosts will passively drain at a rate of 1 level every 60 seconds.
This guide will go over all of the boosting items for the herblore skill and will breakdown which boosts are the easiest to get for both main accounts and ironmen.
Item | Boost Type | Level Increase | How to get the boost |
Greenman's Stout  | Visible | +1 | Purchased in the Dragon Inn in Yanille. Purchased from Rasolo south of Baxtorian Falls Purchased from the Lighthouse Store in the Lighthouse |
Herblore Cape  | Visible | +1 | Obtained by using the boost feature on the herblore skillcape after achieving 99 herblore |
Mature Greenman's Ale  | Visible | +2 | Fermenting it yourself (takes up to 5 days) |
Botanical Pie  | Visible | +4 | Made by combining a golovanova fruit top with a pie shell and cooking it at 52 cooking. |
Spicy stew (brown)  | Visible | ±0-5 | Obtained by combining 3 brown spices with a stew to make a spicy stew after completing Evil Dave's portion of the Recipe for Disaster quest. This is not a guaranteed boost and can boost the players level anywhere from -5 to +5 |
The easiest herblore skill boost achievable for mains would be buying the botanical pie. It provides a +4 boost to herblore that is guaranteed unlike the brown spicy stew which can only give up to a +5 boost and it is heavily luck dependent.
The easiest herblore skill boost achievable for irons would be the botanical pie. The golovanova fruit top is obtained by thieving fruit stalls at a rate of 1/50 making it relatively easy to get in comparison to a boost from the spicy stew.
Visible skill boosts refer to boosts that directly affect your level and you can see in your stat breakdowns. With some exceptions, if you have a visible boost past your current level, it will allow you to interact with the skill in ways you would not be able to at your current level. An example of a visible skill boost would be eating a slice of the botanical pie to get a +4 boost. Instead of needing 81 herblore to make a saradomin brew you would only need 77 with the pie, making this exceptionally good for ironmen.
Players who have unlocked the Preserve prayer with the torn prayer scroll will make this drain 50% slower putting it at a 1.5min delay per level drain. Players must have preserve active for 15 seconds before the stat drain delay starts to work.