Hydroponic buckets are not, strictly speaking, intended for plant germination, for a variety of reasons which we discuss below. Thankfully growers have a number of options available to them. The above three options are all available at Amazon.com and from a variety of online hydroponics retailers. They are actually aeroponic systems which spray either water or nutrient solution onto seedling starts, which are held in the bucket lid. The starts can then be transplanted into buckets after their root systems have developed further. An Internet search on "DIY hydroponic germination" or "DIY hydroponic cloning" will bring up many variations on this theme.
The short answer is, yes. The bucket system can theoretically germinate seeds and foster their growth from germination to full production. The longer answer is yes, with several caveats, and not as efficiently as other methods. Let’s take a closer look at those details.
I should start off by saying that bato buckets are not normally used for germination. The system’s strength and advantages come from being extremely cost effective for growing a certain group of vegetable crops which other hydroponic systems can’t match. We’ve already looked at a variety of those advantages. The downside of bato bucket production is that while the system can theoretically provide germination, several inherent design features of the bato bucket system either cause problems or need to be resolved somehow.
First and foremost, bato bucket systems generally take up a lot of room, and germination doesn’t need that much space. Consider that any given crop’s germination space will be a tiny fraction of the plant’s final size. A bato bucket’s individual volume, depth, width, etc is based on the mature plant’s root zone volume. As such, that’s a lot of wasted space during germination and the first month or two of growth. Similarly, the spacing between buckets is based on the crop’s mature size, height and shape. For instance, a big bushy plant like rosemary will have different bucket layout than a vining crop such as tomatoes. Yet both crops wouldn’t need that much space until the plants reached production. While the buckets could be spaced closer together at first then spread out later, that’s a lot of hassle factor moving irrigation lines around. Drain lines are another complication, if the system is plumbed for drainage.
Secondly, the nutrient delivery system would be working at full capacity when only a fraction of the nutrients are actually needed during seedling growth. While the seedlings themselves would only take up the nutrients they need, and a recycling system would be able to keep recycling the unused nutrients, the system would still be drawing power and water; resources which a grower would need to pay for. For hobbyists with only a few buckets, this might not be a huge issue. However, even two dozen buckets for a large hobby setup, or a small commercial setup, would start to cost a lot more than necessary.
A third issue is that the growing media would have to be very carefully selected. This is not only to match the growing media to seedling size but also to ensure that the nutrient solution will wick closely enough to the seed to keep it hydrated. If the seeds are extremely small, such as with lettuces, some herb crops and many brassicas, most growing media types would be unsuitable. The growing media particle size would be so much larger than the seeds, that seedlings could easily be dislodged from their ideal planting depth, and either float up too high, or drawn down too deeply into the media. Either would result in seedling death. In this instance, the crops are almost always germinated elsewhere, then transplanted into the system after root growth is well along. Medium- to large-sized seeds such as tomatoes, beans and peas, some herbs and the squash family aren’t as prone to being dislodged, but still need a fine-textured seedbed to maintain correct position. If a grower already intended to use one of these growing media for the mature crop, then it would be relatively easy to germinate the crop in place, and let the roots expand into the full bucket volume. However, if the grower wanted to use some other growing media, perhaps due to cost or recyclability, he or she would need to very carefully pencil out the options to see if in-place germination is really the most cost-effective solution.
The growing media would also need excellent wicking abilities such that the seedlings would maintain ideal or near-ideal hydration levels. The seedlings’ lack of mature root system would need frequent hydration, yet also have excellent drainage. Conveniently, the small-particle-size growing media described above usually also has excellent wicking abilities, so the same growing media can serve well on both fronts.
Fourth, a grower would need to very carefully manage the surrounding humidity surrounding the seedlings. Seedlings have very specific moisture requirements; too much or too little and the seedling either dries out or succumbs to fungal disease. At the growing media surface, and within the growing media growing zone, the humidity can be controlled via frequent irrigation and good drainage. However, the atmosphere immediately above the growing media surface also needs to be very carefully managed, and bato buckets aren’t by themselves designed for this. Growers would need to develop caps or lids for their bato buckets which would allow for sufficient light transmission yet preserve the proper humidity levels. While standard seedling flats have well-matched clear plastic lids to provide for this exact issue, the same cannot be said for bato buckets. A grower would have to come up with some kind of DIY tent system. That hassle factor would very quickly require more time, money and/or energy than simply germinating the seeds elsewhere.
If a grower is absolutely determined to germinate seed within the system, a hybrid approach might be practical. A portion of a bato bucket system could be set aside for germination purposes. Within that section, those buckets could be used as mini flood-and-drain containers for multiple seedlings per container. The buckets themselves could be arranged immediately next to each other rather than spread out, and the irrigation/drain lines arranged accordingly. Whatever growing media the grower wants to use, could be used within this section regardless of what growing media he or she is using for the mature plants elsewhere. Rather than enclose each bucket with a lid of some kind, the buckets together could be contained in a group tent or mini-greenhouse, to maintain optimal temperature, light and humidity levels. The irrigation cycle might need its own reservoir to provide for the seedlings’ nutrients, which are often quite different than for mature plants. That reservoir system could have much more frequent cycling too, as compared to the rest of the system. Then as the plants grow large enough for transplantation, they could be moved into the rest of the system, and then maintained as mature plants.