Beyond the Basics

Because I am one of the world's few farmers who has chosen to grow hydroponically, I am constantly approached with the same old questions on what to grow, how to grow it, maintenance requirements and pest management. My commercial experience is limited to peppers, basil and to some extent, tomatoes and lettuce; however, I have been growing hydroponically for years, experimenting with all kinds of crops. Some flour ished; some flopped, Currently I am growing sweet peppers and basil commercially, so I will use these crops which have very different needs-as examples to detail most everything you need to know about hydroponic growing for a mix of crops. It's a good idea to clean the system between plantings to prevent the spread of disease or fungus growth.

It all starts here, and this is what determines-for the most part-how your fruits and vegetables are going to taste. I buy solely for taste, not to save money. Taste sells, so it's ultimately worthwhile to buy the best seed varieties, no matter how costly they may be. Today's competitive world of agribusiness emphasizes quantity at the expense of taste, so most hydroponic growers, like organic farmers, are fulfilling the consumers' desire for high quality fruits and vegetables. When purchasing seeds, you should also consider the fact that some plant varieties-even those of the same species-will mature faster in less space than others. There are no particular seeds that will grow better hydroponically than others, just choose those that are best adapted to your climate. Any good seed supplier will provide you with the information you need. For unusual varieties you may even be able to find some interesting varieties for a decent price in some traditional catalogs.

"Gypsy" is perhaps the best tasting red pepper variety; it's what I chose to grow at White Owl WaterFarm. They are vigorous, prolific plants able to grow like a vine so they won't take up too much space. The only drawback is that their fruit isn't very heavy. "Vidi," on the other hand, produces enormous fruit and provides a dense foliage which protects the fruit from sunburn and shades the nutrient solution to maintain cooler temperatures in summer. "Ariane" is an excellent orange pepper plant which produces big, beautiful fruit; unfortunately, this variety can be tricky to grow. It will thrive in a stable environment like Holland, where it was developed. As far as yellow peppers go, I have yet to find a variety that really satisfies me, but I settle for another Dutch variety, Quadrato d'Oro, since consumers usually want a range of colors.

For basil, I prefer "Perfume Genovese," an Italian variety. It has a very subtle, yet rich taste and an incomparable scent. This variety is highly susceptible to fungi, but its taste is worth the extra effort in maintenance. All of our seeds are started in flats with a transparency cover to trap heat in winter. As a medium, we use a mixture of peat, vermiculite and perlite. Sometimes I do it myself, but most often I buy it pre-mixed with pumice and bone meal (Whitney Farm seed starting mix). We sow the seeds in four rows, taking into consideration the mature size of the future plant. Both pepper and basil seeds germinate easily; we routinely achieve a nearly 100 percent success rate. The mix should be very moist at all times, and it's important to feed the young seedlings as soon as they develop their first set of leaves. We feed our starts a stronger nutrient than normally prescribed. Once our plants have fully germinated, they are watered each day with 450 ppm for two days, then 850 ppm for the following two or three days, and then with pure water for another two or three days. We continue alternating between 850 ppm and pure water until the seedlings are ready to be transplanted. Keep in mind that this schedule and the nutrient levels vary according to such factors as climate, light levels and air circulation.

From the moment your plants sprout, you will have to inspect them closely at regular intervals to detect any early signs of disease or pests. It takes time to learn how to interpret the signs, and some may never be diagnosed, but detection is the real key to success. It's essential to examine your plants on a regular basis; in fact, it's perhaps the most important aspect of plant maintenance. Our seedling are transplanted as soon as they can extend some roots below, and some stem above, the three-inch net cup filled with "Growrocks." First we rinse the peat mix out of the roots with a garden hose and lay the seedlings in a deep tray filled with water until they can he placed in the grow cups.

We use a separate system to mature the new plants for optimizing crop rotation and saving space. When first transplanted, the seedlings are placed in General Hydroponics'Acrofio model 384, which is designed with seven inches of space between the grow cups and seven inches between the rows. This allows enough room for 384 plants to mature before they are placed in the production units. People have given much thought on how to maximize their growing space in a greenhouse, but no one seems to agree on one solution. Naturally there's a limit to the number of plants you can grow in a given space, and greater yields may be obtained from fewer, bigger plants rather than many small ones. I personally prefer tight spacing. Our peppers and tomatoes are grown with only 14 inches between plants and 14 inches between rows. For basil, we put two to three plants per pot with seven inches between them and 14 inches between rows. Although one single adult basil plant would fill up that space and more alone, greater yields can be had in less time this way. Then when the plants are bigger, the unhealthy ones can be taken out of the system, sometimes leaving just one plant per cup. Our plants are rotated on an ongoing basis, so each plant site sees approximately three generations throughout the year.

Growing in a greenhouse is obviously much different from growing outdoors. Generally there is much less horizontal space, so it is necessary to make the best use of your vertical space. Pruning your plants so they grow as vines rather than bushes is a good way to achieve this. Also, you may want to channel their growth into "leaders" to prevent early fruiting since the growing season is much longer in a greenhouse. There many different pruning methods to train your plants as described. Following is a description of the techniques that I use.

Our peppers are grown on two leaders that are trained to form a V-shape and angled in a manner that gives each branch its own space. After experimenting with many types of string, we have settled for mason line since it's cheap and strong. It takes a fair amount of time to install strings for pepper plants (two per plant), but once in place they can be reused for years with only minor repairs. Using the strings to guide it, the plant will naturally fork into two, often three, branches. In the case of three, one will have to be cut. A flower will appear on the first fork; that should be removed. Remember: you don't want to spend the plant's energy on fruiting when it's so young.

Lateral branches will soon develop and a flower will bloom at the junction with the main stem. That flower can fruit, as well as the next one along the lateral branch. At that point, we pinch the branch. Some species such as Gypsy, will easily grow like a vine without much lateral pruning, whereas others will tend to develop too many branches. All pepper plants develop an excessive amount of fruit, so you will have to limit the number throughout your plants' life.

For maximum air circulation and light penetration, you should limit the growth on the plant to the uppermost three and a half to four feet. Do that by cutting the lower branches after they bear fruit. Cut all the bottom leaves as well as the suckers that might grow from the lower stem. In short, leave a clean stem. Unlike tomato plant stems, pepper stems are too brittle to lay over the system pipes or on the floor, so keep your system low to the ground. This will enable you to have a long growing season and to harvest at a comfortable height. Pinch the leaders to stop further vertical growth when you need to. There are no hard and fast rules to pruning. You can replace weak plants with shoots from stronger ones or choose to have three or even four leaders on a pepper plant.

Most growers choose not to prune basil, preferring to harvest the whole plant. Because they tend to grow elongated branches, I prune in order to keep them bushy; however, I always leave a new growth by cutting above a knot where I can clearly see two new heads growing out of the stem (see figs. 3 and 4). If you do decide to cut your basil plants, how you proceed depends on whether you are harvesting for sale by weight or as bunches. In the latter case, you will obviously need some stern, so cut the plant shorter.

Our water culture system is equipped with a float valve in the reservoir so it can easily be hooked up to a faucet to maintain the nutrient solution at a constant level. The pH and conductivity of the solution is adjusted daily, although it's not fatal if you miss a day here and there. There are devices on the market that can keep your pH perfectly stable at all times, but if you want to keep your operation as simple as possible and to limit capital investment, this is not the way to go.

Another way to keep it simple and keep costs down is to operate the greenhouse on thermostats. Computerizing the greenhouse is extremely expensive and rather difficult to manage for beginners, but this may be the perfect choice for someone who is both a gardening and computer enthusiast. That is an option, but a "ridge vent" is a necessity. You can never get enough air in your greenhouse. Position the vent in relation to prevalent winds. They will bring a flow of Co2, cool your crops and reduce moisture. Don't cut your greenhouse off from the outside world. Unless you have enormous sums of money to spend on creating a nearly perfect artificial environment, this just won't work; you need the natural elements.

Cooling might also be a necessity. The temperature of the nutrient solution should not exceed 75?F (24?C) or drop below 60?F (16?C). If you don't use a cooling system, you will need good circulation fans. Prepare for the hot weather; purchase a good plant canopy to cover your growing chambers. This will keep the temperature of the nutrient solution at a tolerable level. Because their roots are immersed in oxygenated water all the time, your plants will not close their stomata and stop growing when air temperatures reach 80? to 85?F (27? to 29?C) as they would in soil (or in some other hydroponic systems).

We have experienced extreme temperatures with little or no damage to our crops. The highest temperature that we have recorded in our greenhouse was 11?F (43?C). At this temperature, the air inside the canopy was around 93?F (34?C) and the nutrient solution did not rise above 83?F (28?C). All these temperatures are of course, far from ideal. For most crops, you should try to keep your air temperature between 60?-65?F (16?-18?C) at night and at a maximum of 85?F (29?C ) during the day. Your nutrient solution should be from 60?F (16?C) to a maximum 75?F (24?C).