Crop focus: tomato

When determining which crop to grow in your hydroponic greenhouse, growers should factor in a number of variables, including: the market for the crop, the timetable for growing and how to grow it. Maxwell Salinger, horticulturist for CropKing, helped answer some of these questions for tomatoes.

Produce Grower: Why should growers be producing tomatoes? What’s the appeal of the crop?

Maxwell Salinger: Compared to other vegetable crops, tomatoes have a very high demand level that spans across a lot of demographics. Whether you are selling at a local farmer’s market, directly to restaurants, or to a grocery store, tomatoes are fairly easy to move.

One of the main benefits of growing tomatoes in a greenhouse is the drastic increase in fruit quality, both in taste and appearance.

“Without pest or environmental pressures, the fruit is allowed to develop blemish free, in perfect symmetry; and we all know that a vine-ripened fruit will blow away the competition,” Maxwell Salinger, horticulturist for CropKing, says.

When you pair this increased quality with the ability to produce a local crop at a time when there is nothing coming out of the fields you have a recipe for success.

PG: Which systems are best for growers who might be converting part or all of their ornamental production?

Maxwell Salinger: There are a wide variety of growing systems utilized for hydroponic tomato production, and they range quite a bit in complexity.

The main component of any system is the growing media and container. The most popular media that is used in the United States is Perlite. Perlite can be used in plastic grow-bags or Dutch Bucket systems.

Plastic grow bags are probably the most inexpensive when it comes to initial investment, but they need to be replaced every year. For this reason, many growers opt for the use of Dutch-Buckets that can get re-used.

The other type of system that is often used is the hanging gutter system. This is where slabs of rock-wool or cocoa are placed in long gutters that drain the nutrient solution to the back of the house.

Regardless of which system is used, the irrigation is very similar, typically a drip-emitter ranging from ½ -2 GPH is used to feed each plant individually.

PG: What is the market for greenhouse grown tomatoes? Where can growers sell their produce?

Maxwell Salinger: Greenhouse grown tomatoes can be sold in a wide variety of venues, but the most profitability comes from the direct sales.

Although these direct sales will only account for a smaller portion of total sales, they can often be the most lucrative. Often ornamental growers already have an established customer base that visits their market and this is the perfect place to enter the market.

Wholesale also makes up a large portion of many growers’ sales and higher-end grocery stores are usually willing to pay a premium for a superior quality product.

Restaurants that use fresh produce are another great market, but often the margins are slightly lower than that of direct sales, while proving just as much headache.

PG: Generally speaking, how long is the growing process?

Maxwell Salinger: Hydroponic tomatoes are typically started in mid-December to mid-January and first fruit is usually harvested 100 days after seeding. These plants are then harvested until October when fruit loads are getting close to 30-50 pounds per plant.

PG: What are some of the challenges growers might face with tomato production and how might they overcome them?

Maxwell Salinger: Some of the biggest challenges that hydroponic tomato grower’s face center around the longevity of the crop. While we can drastically improve our plant’s potential total harvest weight by harvesting for eight months, we also open them up for potential infections. This is why plant health maintenance is so important.

Regular scouting of the crop and proper plant management is imperative. Tomatoes in particular are susceptible to several root diseases, pest infections and fungal diseases such as powdery mildew. By keeping our plants as vigorous and healthy as possible, we are able to stave off many of these infections.

Managing our crops vigor is also important in maintaining an even harvest throughout the year. By pruning our plants into single leaders, we are able to focus the plants main energy to the fruit production instead of unproductive branch growth. A fine line between vegetative and fruit production is often walked in order to optimize production while still maintaining our plant’s health. These practices often become incredibly important when it comes to vegetable crops as opposed to ornamentals because our pesticide and herbicide “tool-box” is more limited.