Urban Farming Insider: Understanding organic hydroponics with Tinia Pina

Tinia Pina is the founder and CEO of Renuble, a company started in 2011 that develops hydroponic fertilizer 100% derived from organic food waste inputs.

Urban Farming Insider: Understanding organic hydroponics with Tinia Pina

Renuble helps hydroponic growers increase yields with a wide variety of urban farming crops grown hydroponically in large metropolitan areas like New York City, where Renuble is based.

We interviewed Tinia to discuss:

- the basics of organic hydroponic fertilizer for beginning urban farmers
- some brand names she hears often for lighting, growing medium, common urban farming products
- and more!



UV: Can you start off by talking about Re-Nuble and how it started? What's your mission?

Tinia: I founded Re-Nuble in 2011, the whole premise behind that was to try to increase access to more nutritious options, primarily in cities, because I saw that's were the trend was as far as macroeconomics of people migrating towards (cities).

So, how can we make food, especially nutrient dense food, more affordable, and by doing that, making use of the abundant food waste in New York City and more efficiently serve the needs of food production.

My vision to achieve that was re-purpose or up-cycle the reclaimed nutrients from food waste and at the time New York City was spending 33 million dollars (per year) to export its food waste.

We thought that by manufacturing value added, organic liquid fertilizers, primarily within the hydroponic industry, because there was definitely, and still is, a demand to grow with organic inputs, it is challenging... but we've proven that you can achieve comparable grow results.

Granted, the nutrient management side still takes a bit of a learning curve to adopt, before (using this type of fertilizer is really seamless.

So the goal is to indirectly increase food production in cities so that we can cover the crisis of food with more supply.

UV: You mentioned the learning curve for hydroponics, can you talk about what that entails? Obviously, with the company being around since 2011, you have a really good perspective on how hydroponics have been trending in the urban farming setting since then. What's your perspective on that? 

Tinia: We started in 2011 with a different business model, we pivoted into hydroponics because the problem was more prevalent with using organic fertilizer and meeting that demand, (the pivot was) only as of 2015.

The challenge with organics or anything that's biologically derived is because it's so natural, you can't have the precision that you have with a synthetic fertilizer where it's already in its ionic form and readily available to the plant.

(With synthetic fertilizer), you know exactly to the parts per million what ionic nitrogen or phosphate or mineral is available to the plant.

With biologicals, a lot of the decomposed matter, for example, in ours, we have organic certified produce waste, that decomposed matter still goes through a degradation when it is subjected to a hydroponic reservoir (unlike synthetic fertilizer).

So (biological fertilizer) is still decomposing when you're in a hydroponic reservoir, and that lessens the ability to have precision and know exactly how much your pH or EC will be, especially within the first 1 or 2 weeks of growing, and that tends to stabilize after that.

UV: When you say "the first 1 to 2 weeks" what is that 1-2 weeks referring to? Is it to after application of the fertilizer? 

Tinia: When the fertilizer is bottled, we're guaranteeing, a six month shelf life, so it is pH stable (pre application), and then when you dilute it in your hydroponic reservoir, it does go through a natural decomposition because the microbes are active again, so to answer your question, the pH and EC swing after application into the hydroponic solution due to microbe activity, so you're unable to say "you can expect with certainty a pH of 6.5 within the first 2 weeks simply because biological fertilizer has to normalize.

We've shown historically, it's at that two week mark, that your EC swings, anywhere from .8 to 3, then tends to normalize, and that's only for hydroponic reservoirs.

In soil, because you have the soil and you have a medium that diffuses, the microbes act differently in the soil medium, just like they would in rockwool or similarly in coco coir. How the organic fertilizers act in those substrates has less effect on your EC and your pH.

UV: You touched on a ballpark EC range, what is a range for pH (for hydroponic mediums)? Does it depend on the crops you're growing? 

Tinia: So what we do with our product line, we have an Away We Grow, which is a grow formula, True Bloom, for flowering, and fruiting crop formula, and a supplement which does really well with microgreens but it's a supplement at the end of the day.

So we advise (pH level in hydroponics) on a benchmark. With biologicals (fertilizers) you aren't able read EC technically because there are no mineral salts, but we show based on our own trials that EC of 1.8 for butterhead leafy lettuce for example, it will be optimal to maintain that EC for the 4 or 5 week duration that you're actually cultivating it for.

Then we prescribe a pH range (only) if you were using synthetics.

UV: To clarify, the reason why you can generate this data on EC and others can't is because your essentially doing some type of simulation? Is that a fair way to say how you derive your EC benchmark of 1.8? You essentially said with the EC that you can't technically measure it, then you said is you guys do project it for the edification of the customer. What are you doing that the customer can't do as far as simulating EC? 

Tinia: The customer should already be measuring their hydroponic solution for pH and EC, the only big difference is, say (For example), you often have a pH stick that also measures for EC, if you were to subject it to a reservoir that has our nutrients in it (organic fertilizer), it's going to "dial" or measure an EC value, but, there really is no salts that are in the solution, so the (reading) isn't accurate.

So what we do is project the EC so that we can tell you what to look our for, but (at first), there isn't a true measurement because technically there's no salt's in there at the end of the day.

UV: So this at the end of the day, is a very technical aspect of hydroponic nutrients? 

Tinia: Yes. With organics in general, it can be grown just as effective, as far as leaf size and harvest weight, it can take a little more time to get the same harvest weight compared to synthetics, and that's expected because it's a slower uptake process.

But you can grow with organic fertilizer just as you can grow with synthetic fertilizer. This same reason is why Re-Nuble has gotten so much interest - people want to have a more viable alternative to synthetic hydroponic fertilizer, it's the same with food and medicine, it speaks to the same cause (to not rely on synthetics).

UV: For people who are looking at the unit economics, cost and benefit analysis, maybe they're thinking about starting their own urban farming hydroponic operation, what do you look at when you're looking at the cost of say, a biologic fertilizer compared to say, a synthetic one?

When crops are grown and harvested, what do you typically see as the mark-up for the organic hydroponic produce you're typically helping your customers grow? 

Tinia: We've seen to date that just organic or natural branded crops tend to command a ~44% pricing premium.

That mainly pertains to metropolitan areas, we've done less testing with rural, traditional farmland areas.

Now, (on the unit cost side), you will notice that with organic hydroponics you will typically need more applied fertilizer than with synthetic fertilizer.

As I mentioned earlier, this is because synthetic fertilizers already provide the nutrients in ionic form, which just means it's readily available for the plant to pick up, whereas with organics, there's still a requirement for the plant to convert (the organic waste based fertilizer) into a form that can be picked up.

So what that essentially means is that you will need more organic fertilizer to get to the same needed concentration, compared to synthetic fertilizer.

I typically estimate you will need 20% more of the organic fertilizer than with synthetics, but if you're selling the (organic) urban farmed produce, and you can sell it higher, it's typically worth the cost!

UV: So you're applying 20% more, on a unit basis does organic hydroponic fertilizer cost the same amount as synthetic hydroponic fertilizer? How does it compare? 

Tinia: It depends on the production scale, the water, the temperature. It does become technical to answer that question because all of these variables, water, temperature, the crop type sometimes, the moisture, the air in the actual grow space, can slightly increase or slightly decrease the nutrient consumption.

So I can't give a (generalized) baseline for unit cost unfortunately.

UV: Another thing I get asked about is, especially for setting up a hydroponic system, is regarding the most commonly used / popular brands, I'm not asking you to talk as much about the fertilizer but when you're interacting with customers, what are some of the common names you see them using for the actual hydroponic system, for the tanks, for lighting, what are some of the popular names that you're hearing about more often? 

Tinia: What I'm hearing from people, anywhere in between New York City, Florida, DC, and a couple people on the west coast, for lighting I've heard Lumigrow. They tend to be a popular brand on the commercial side as well as hobbyists.

For the organic base (hydroponic nutrient fertilizer / "grow formula"), depending on what you're growing, people have said Pure Blend, which is part of Botanicare, that's a brand that we directly compete with, and we've shown better yields for some crops for Botanicare, the main differentiation between Runuble and Botanicare is that Renuble has 100% organic certified inputs whereas they say they have an organic base but they do incorporate synthetics into their (fertilizer) formulation.

On the medium side, I hear Growdan (rockwool cubes) a lot, with hydroponics, surprisingly users taking a blend of perlite and mixing it with cocoa coir, kind of a hybrid set up, on the soil side, what's been popular is Batch 64, depending on what your growing, they have Batch 64 and then Waste Farmers.

The reason why I'm speaking (about) these brands is because they (the brands above) are for people interested in sustainable grows, and those that have more of an organic alignment.

UV: I like to finish up with some rapid fire questions. What's a company in the urban farming space that your excited about / that you think is onto something, that you've been following, maybe a CEO that you've been following in the space?

Tinia: One is called Farm.One. Instead of the retrofitted shipping containers they take microfarms and they provide specialized growing services but focusing on really exotic herbs. So they're really taking an angle of (growing for) culinary art to a whole other level and not just producing your typical commodity crop.

UV: The next question would be what's your favorite fruit or vegetable? 


UV: What's your favorite book relating to urban farming? I know that's specific and there may not be that many books, so if you don't have an idea for that what's one of your favorite books in general, one that is most gifted or that you most recommend. 

Tinia: I have quite a few! There are books on my bookshelf that I haven't even read yet but I'm wanting to. But answer your question, "The Vertical Farm", by Dickson Despommier, which is cliche now.

UV: The last question is, what's something you disagree with or think there's a misconception about in the urban farming industry or hydroponic industry that is generally accepted as being true?

Tinia: It's less of the hydroponic industry but more of the agricultural industry in general, but I'm not sure if you know, but this April 17th, anything hydroponically or aquaponically grown that wants to obtain organic certification is being voted as to whether it can obtain that certification. 

So the contention that I want to bring up is that hydroponics and aquaponics, anything in the controlled environment industry, can be successfully synergistic with conventional ag. I think right now, because there is a market, it does impact a lot of people's bottom line. If they open up the organic certification process, I think a lot of people think they have to be competitive and contentious but they can very much complement each other (conventionally organic grown produce vs controlled environment organic agriculture) very much.

Thanks Tinia!

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