IC2 Crops Guide

This page contains a guide to progress through IC2 crops and take advantage of the many kinds of renewable resources they provide. For a list of crops, see IC2 Crops List, and to read about crop mechanics in more detail, see IC2 Crops.

Crop breeding can be started in the Steam age, but it becomes much faster and easier with the Portable Scanner, which requires HV circuits, which are late MV (Kanthal EBF is needed).

TL;DR

There are many different crops, and each one has different outputs. Their growth speed depends on their Growth and Resistance stats, alongside the environment stats, while their output amount depends only on their Gain stat.
Each crop has a seed type. There are some crops, like Sugar Cane, that can be planted on a cropstick by using the item, but most others need a seed bag that is obtained from an existing crop of that type. To get the first seed, you need a random mutation through breeding.
Seed bags will drop often from crops that are fully grown, but not always, and the best way to do get them is to left-click without a Spade. However, they can also drop from crops at any growth stage, with a Spade right-click, with a lower chance.
Weeds will appear on cropsticks without a crop, unless they have Weed-EX. They will spread to adjacent cropsticks, with or without crops in them, if they grow to their last stage, and any crops at 24 Growth or above will also spread weeds this way.

General Crop Summary

Begin by crafting IC2 Cropsticks and searching for Sugar Canes in the world. When you have some, right-click wet, tilled soil with the sticks to put them down (wet soil makes the crops grow faster).
Right-click the cropsticks with the canes to plant them. This creates Reeds, the name of the plant that ended up in the cropstick.
Wait for the crop to grow fully and right-click it to get some more Sugar Canes.
Place down some more Cropsticks. Put two of them on the same dirt block to make double cropsticks, surround it with Reeds and put more double cropsticks on the corners to make a 3x3 field. The double cropsticks allow for the crossbreeding of the Reeds, originating more of themselves or a different kind of plant at random.
Watch out for weeds! They can show up in cropsticks without a crop inside (double cropsticks too), and if they are allowed to grow, they take over adjacent cropsticks and replace the plants inside. Destroy the cropstick if a weed appears, right click with a Spade or use Weed-Ex to prevent the weeds from appearing for a good while.
Make more of these 3x3 fields, or expand the first one, alternating between Reed and double cropstick. Keep doing this until you get Stickreed. Be careful that Stickreed is different from Reed, but looks the same in the first three growth stages! Use a Plant Lens to see what crop it is, or a Portable Scanner if you have it.
Keep crossbreeding until you have a lot of Stickreeds, and replace the Reeds you had with those. The objective now is to crossbreed them to get better crop stats.
To see crop stats, the early option is an LV scanner, but it needs harvested seeds to scan, which needs the crop to be fully harvested as well. To avoid this, make a Portable Scanner and right click planted crops to see their stats right away.
Crop stats start at 1/1/1 for Growth/Gain/Resistance and change slightly from the existing crops to the new one, at random. Since Stickreeds grow very fast and are Tier 4, unlike most of the other fast-growing crops at Tier 1, keep crossbreeding and replanting the new crops that have better stats than the ones you have. The objective is to get 21/31/0 for Stickreeds used to spread high stats to other crops, and 23/31/0 for crops meant to be harvested in an automated farm.
While crossbreeding for stats, pick all the different crops that show up over time and store their seeds. To reach most of the useful high-tier crops, start with the ore crops obtained from crossbreeding Stickreeds and cross those, aiming for higher and higher tier crops until you reach Platina. These need Platinum Blocks to grow fully, which might be unavailable, but they can still crossbreed without the block at growth stage 3.
When both steps are done, crossbreed the max-statted Stickreeds with other crops to transfer over the high stats. To obtain other kinds of crops that haven't showed up yet, the NEI tab on the seeds is useful and a good path to follow.

How Stats Benefit Crops

There is a total of 6 stats that affect how productive a crop is. Three of them are crop stats (Growth, Gain, Resistance), and the other three are environment stats (Nutrients, Humidity, Air Quality). Crop stats can be manipulated by crossbreeding or other methods, and are specific to the seed bag, while the environment stats depend on the block where the cropstick is at. Environment stats all work to boost the growth speed of the crop.

Growth affects how much the crop grows per random growth tick. The higher it is, the faster the crop grows, up to 31. However, if this stat is at 24 or higher, the crop gains weed behavior and will place weeds in adjacent cropsticks, even if there are regular crops in them. To prevent this in your automated farm, make an X formation with no adjacent cropsticks, make a formation with varying Y levels to prevent adjacent cropsticks, or use the Industrial Greenhouse.
Gain affects how many items the crop outputs, on average, when harvested. This is applied on the default number of drops, which varies from crop to crop, and goes up to 31. There's no penalty to maxing this stat, so 31 is always best.
Resistance affects the chance of a seed bag drop when the crop is harvested off the cropstick, and also lowers the chance of a weed spawning on the cropstick from adjacent weeds. However, increasing this stat also lowers growth speed slightly, because it makes the crop more demanding of environment stats, which makes them less effective.

These stats can and should be worked on for a fast and efficient automatic farm. For a completely filled farm with the same Y level, the most efficient stat spread is 23 Growth, 31 Gain and 0 Resistance (23/31/0). If you have a setup that doesn't have adjacent cropsticks, the best spread is 31/31/0, which also applies to the Industrial Greenhouse.

Nutrients depend on the biome the crop is in, more specifically the "Nutrients" stat of the biome, which maxes out at 10. On top of that, it can be boosted by up to 4 points by having up to 4 Dirt blocks under the cropstick, with a cap of 3 points for the crops that needs a block to grow fully (this block should be at the bottom of the 4). Finally, using Fertilizer also boosts the Nutrients stat: the Fertilizer value of a crop ranges between 0 and 200, and it increases the Nutrients stat by up to 10, but it can only be applied when the Fertilizer value is under 100, which means the baseline for this boost is 5.
Humidity also depends on the biome the crop is in. To boost it further, use Farmland under the cropstick (2 bonus points), and make it wet from nearby water (another 2 bonus points). Finally, hydrate the crop with an IC2 Hydration Cell for an extra 10 points, or provide water to your machine automation, which will hydrate crops for you.
Air-Quality gets higher with a higher y level, up to 4 points at y=124 or above (y=79, 94, 109, 124 for 1, 2, 3 and 4 points), with another 2 points if the cropstick can see the sky (no blocks or only transparent blocks above). On top of that, the 8 blocks that surround the cropstick at the same y level are checked: 8 air blocks means 4 bonus points, otherwise 4 or more air blocks means 2 bonus points.

Based on this, maximizing the efficiency of your farm means choosing the right spot for it. The biome it's in is very important, check here for a spreadsheet of the best biomes. The biomes for highest stats are Fungi Forest, Lush Swamp, Moor, Rainforest, Tropical Rainforest and Tropics. On top of that, putting the farm at y=128 or above is best. Until you have all of the Farmland blocks occupied, it's also a good idea to scatter the crops, so that they have the highest Air-Quality stats possible until the farm is completely filled.

One important thing to keep in mind is that every crop has a "need" for stats. That means that, depending on what crop it is, its tier and stats, it has a baseline of environment stats that it needs to grow at all. If they are not high enough, the crop can die, and just disappear from the cropstick. The higher the tier and crop stats, the more demanding the crop is of environment stats, so a max-statted tier 12 Transformium, for example, will most likely not survive in a bad biome for crops.

If it survives, however, its growth speed also checks the crop stats, and higher crop stats slow down its growth. However, this decrease is minimal, around a few % per high stat, much lower than the boost that high Growth and Gain can give. This is the reason why 0 Resistance is best for optimal growth in a good farm location, because it doesn't increase the speed of outputs and actually decreases it slightly by adding to the total stat check.

Given all this, it should be noted that the most demanding crops get boosted the most if you optimize your environment stats. Every point increase is a bigger difference for them, and as such you should pay close attention if automating max-statted crops such as Transformium, Stargatium, Space Plant, etc.

Automating

All IC2 crops can be automatically harvested for their resources when they reach their final growth stage, and return to an earlier stage without needing to be replanted. Instead of doing it all by hand, it is possible to use a singleblock (Crop Harvester) at LV, or a multiblock (Multifarm) at HV to harvest crops for you.

The Crop Harvester is often paired with another singleblock, the Crop-Matron, which automatically uses water, Fertilizer and Weed-Ex on all crops within a 9x9 square centered on it. The Harvester has a slightly bigger range, 11x11, and only does the harvesting. They each use 1 LV amp to run continuously, and together they need 2 amps to keep all crops growing fast and harvested automatically, but they're cheaper to craft than the alternative if you only need a small farm to automate a handful of crops, and available at earlier tiers than the Multifarm is.

The Multifarm is the multiblock option that does all of watering, fertilizing and harvesting at the same time, but has no slot for Weed-Ex. It is a multi of variable size, from 3x3x4 to 5x5x4 (LxWxH), and the available area for the farm depends on the its size, with the largest one being recommended to extend the farm as far as it can go, given it is a cheap build at HV, the stage where you normally unlock the ability to craft the Uranium Electron Tubes that change the Multifarm mode to IC2 Crops.

The size of the farm for a max-size multiblock is organized as such, being able to cover 1149 potential crops, or 1136 with the water holes:

Diagram of the Multifarm size. The dark green squares in the center are where the multiblock is, the green squares are the size of the multifarm in other modes, and the light green squares show the full size in IC2 crop mode.
Screenshot of a built Multifarm at its max size, with the best layout for water blocks to hydrate the dirt.

It's worth it to note that space for crops has to be sacrificed to add water blocks, but the growth boost that high-statted crops receive from the hydration far outweighs the lost tiles.