The 
Growth of a province, horde army or Black Ark is a measure of the expansion of its population. Growth leads to the accumulation of 
Population Surplus, which is required when upgrading a settlement or horde army.
For hordes, growth is called Horde Growth, and population surplus is required for most buildings, not just upgrading the horde/settlement.
For Black Arks, growth is called Black Ark growth.
For Wood Elves, growth is called Kindreds.
Growth and population surplus can be seen on the Province Info panel, or the Building panel if playing a horde faction. Growth in a horde or province can be stimulated by certain buildings and commandments, and can be hindered by enemy raiding, corruption and heroes.
The population surplus costs for upgrading a settlement are shown on the settlement building rollout on the province Overview panel. More building slots become available when a settlement is upgraded.
For settled races, you can spend Population Surplus to upgrade your town a tier, cancelling the upgrade has some caveats to the refunding. Gold spent is refunded as normal.
- If you cancel before end turn your points will be returned without penalty, and free to be reallocated as you wish.
- After 1 turn of ongoing construction, If you cancel construction your total surplus will be either the current surplus of points, or the number of points to be returned, whichever is higher; effectively destroying the lower surplus and growth.
Quick Tips for Growth on Very Hard or Legendary
An obvious upside to growth is the unlocking of higher tier units and unique high tier buildings, lets take a look at a common player start at Reikland what they should do to maximize growth
For quick reference here is Reikland's Growths on Very Hard/ Legendary
| Tier | Growth Points to reach this Tier | Cumulative Points | Note |
|---|---|---|---|
| 1 | 200 | 200 | Can upgrade towns from tier 1 to 2 using 1 Population Surplus
|
| 2 | 600 | 800 | Can upgrade towns from tier 2 to 3 using 2 Population Surplus
|
| 3 | 1200 | 2000 | Can upgrade towns from tier 3 to 4 using 4 Population Surplus
|
| 4 | 2000 | 4000 | Can upgrade towns from tier 4 to 5 using 5 Population Surplus
|
| 5 | 3000 | 7000 |
A fully upgraded Riekland province (3 tier 3 buildings and 1 tier 5 building) in grand total needs 15000 or 75 turns at 200 growth average to mature.
Empire Buildings that give growth in the province of Reikland are:
| Building: |  Altdorf |
 |
 |
 Pastures |
 Port |
Paved Roads |
|---|---|---|---|---|---|---|
| Tier 1 | +10 | +10 | +20 | +30 | +10 | - |
| Tier 2 | +20 | +20 | +30 | +40 | - | +5 |
| Tier 3 | +30 | +30 | +40 | +50 | +20 | +7 |
| Tier 4 | +40 | - | - | - | - | - |
Province edict gives +20 growth,
And province happiness can effect growth also.
For these assumptions: Province happiness will be 0, and the growth edict will be on, and paved roads will not be considered due to the opportunity cost of not having a usable 3rd building (for smithies etc.)
Build times will be estimated to be 1 turn due to the empires hero trait of noble effectively erasing build times after 3 of them are near a city.
So to get the best growth to get altdorf to tier 5 how should you manage it?
- Should I upgrade my minor settlements?
- NEVER use stored up points beyond 1 or 2, NEVER upgrade a settlement using your 3rd or 4th point since it will use the more expensive points first.
- Normal settlements pay for themselves from tier 1 to 2 in only 10 turns, This is worth it if your growth per turn is less then ~700 (generally always) even moreso for Grunburg
- Normal settlment breaks even after 1000 growth eg. 1 surplus (200) + 2 surplus (800), increasing Settlement and its growth field improves its growth per turn by 20 in total, and so will only pay for its own growth after 50 turns
- Grunburg with its pasture upgrades from tier 2 to 3 with +30 growth from its field, pasture, and settlement building. It breaks even in 34 turns.
- Should I rush Tier 5 with All tier 2 or tier 3 minors?
- Sanity check math: Tier 3 to tier 5 altdorf needs 11000 growth, maxed out growth tier 2 Reikland w/ tier 3 Altdorf gives (90+50+50+90) 270 growth and will grow into a tier 5 settlement after:
- 4000/270 + 1 + 5000/280 + 1 = 14.8 +1 + 17.8 +1 or after rounding 35 turns.
- So using this we can see, Grunburg will (barely) break even, and normal settlements adding 600 growth or about 3 turns on the end
- So 3 turns faster? Does that actually mean anything?
- Not really. Though consider level 10 warrior priests give +40 growth a turn, a good investment that can be used across the whole game.
- Ports are also useful garners or growth, make sure to develop them for an extra boost.