JSS Advantage May 2010

Planting time has arrived, and the seedlings you grew so carefully inside, then hardened off gradually outside, are ready to go into the field or garden. Your goal is to keep them growing rapidly through the transition. That entails avoiding transplant shock, providing the right kind of fertilization, and having irrigation set up so you can water from Day 1.

The phrase "transplant shock" refers to the setback in growth that plants experience when moving from one environment to another or from having their roots damaged by a move. Transplant shock happens to all plants, but most vegetables are able to recover quickly if handled carefully. Here are some strategies for minimizing transplant shock in your seedlings:

• Transplant when your plants are the appropriate size. They should be planted out when they have enough roots to hold the root ball together so they come out of the plug flat easily, but before the roots start to circle or emerge from the bottom of the cell. Old transplants may have reached a reproductive rather than vegetative stage of growth, evidenced by flowering in the cell tray. They will produce earlier, but overall yield will be reduced. Getting them into the ground (if weather permits) before they flower will allow the roots to resume growth and keep them growing vegetatively for a while longer, resulting in stronger plants and better performance all season.
• Water plants thoroughly before taking them to the field. Don't let them dry out during planting! Keep the trays in the shade until you need them.
• Make planting holes, drop in the seedlings, and cover them up as quickly as possible to minimize the time the roots are exposed to air. The general rule is to cover the top of the root ball, to prevent the lighter growing medium around the roots from drying out. If your plants are in peat pots, be sure the top rim of the pot is covered with field soil to prevent the pot from wicking water away from the roots. As with any general rule, there are exceptions. For nightshade crops (tomatoes, peppers, eggplant) the root ball can be buried a little deeper. These plants have the ability to develop adventitious roots from the stem, and by planting them slightly deeper this root formation is stimulated. The roots help to anchor the plant and prevent it from lodging (falling over due to the weight of the fruit). Conversely, lettuce and chicories (endive, escarole, and radicchio) are better planted so the top of the root ball is above the surrounding soil surface. This allows for better air circulation resulting in a reduced likelihood of bottom rot.
• Water the plants, either by hand or by running irrigation right away. Even if the soil is moist, transplants should still be watered in to settle them into their holes and increase the root-to-soil contact.
• Add a dilute water-soluble fertilizer to the watering-in solution. Do not use high-nitrogen fertilizers because they can burn the roots. A dilute, high-phosphorous fertilizer is preferable at transplant. We recommend Neptune's Harvest Fish Fertilizer (2-4-1), which is approved for certified-organic farms, or SeaCom PGR Seaweed Concentrate (0-4-4).

FOLIAR FEEDING

As young plants re-establish in the field or garden, they often have trouble taking up the nutrients they need from the soil. Soil conditions such as high pH, excess moisture, and cold temperatures also can make nutrients unavailable to plant roots. This is often exhibited by purpling or yellowing of the lower leaves on plants. When this occurs, foliar feeding  spraying liquid fertilizer on the plants' leaves and stems  may provide needed nutrients for a short period of time until the roots can resume nutrient uptake.
Foliar feeding has many other reported applications: It can be used at flowering to increase fruit set. It is believed to make plants less sensitive to frost. Foliar sprays of compost tea help prevent plant diseases. And certain nutrient-related problems can be addressed by foliar sprays of the specific nutrient, such as calcium to prevent blossom end rot on tomatoes. More information on how to foliar feed...

The major pathway for nutrient uptake in fruits and vegetables is by the roots, so do not expect foliar feeding to supply all the nutrients needed. Remember the motto of sustainable farming is "Feed the soil, not the plant." Foliar feeding is a temporary measure for special situations, and should not replace cover cropping and soil amendments as recommended by regular soil tests.

Foliar fertilizers should be diluted so as not to burn the leaves. Fish emulsion and seaweed are the preferred foliar fertilizers for vegetables. Not only are they easy to dilute, they also contain micronutrients that are essential to plant health.

Apply a foliar fertilizer by a fine mist sprayer or nozzle. Spray to the point of run-off.

Mix the foliar feed solution in a clean sprayer. When you're done, run plenty of clean water through the sprayer to prevent clogging.

Foliar feed on a cloudy day (but not if rain is imminent), early in the morning or late in the afternoon, to avoid sun damage to the wet leaves. Do not foliar feed on hot days, as the heat can cause plants' stomata to close and prevent absorption of the nutrients.

If in doubt about the success of foliar feeding, use a refractometer. Take a sample before foliar feeding, and then a few minutes after foliar feeding. If the Brix has increased, the plant has taken up the nutrients.

Water-soluble fertilizers can be applied through an irrigation system, a process known as fertigation. Not only does fertigation save time, it also ensures a more even and effective distribution of fertilizer directly to the plants' roots. Like foliar feeding, fertigation can be used to quickly fortify plants that are under stress and unable to take up nutrients from the soil. More on fertigation...

Fertigation requires a system for injecting the fertilizer into irrigation water at the correct rate. The simplest solution is to use a Syphonject, which attaches between a garden hose and faucet and has a suction tube that is placed in a bucket of liquid fertilizer solution. The Syphonject draws up fertilizer and mixes it with water at a rate of 16:1. It is suitable for watering with a hose, but not with drip irrigation. For drip irrigation, a fertilizer injector is required.

IRRIGATION

Drip irrigation is the best way to water vegetables and cut flowers. It avoids wetting the foliage, which can lead to foliar diseases. It delivers water only to the crop, reducing the growth of weeds nearby. And it is the best water-conserving irrigation method, with little evaporation and no wind-blown water. Once a drip irrigation system is set up, irrigating is quick and easy.

A drip system consists of drip tubing, which has orifices at regular intervals that emit water onto the soil at the base of the plants. The water spreads across and down into the soil, creating a uniform band of moisture at root level. Water is emitted very slowly, so there is no runoff. Other components of a drip irrigation system include a filter for well water, to remove particulates that could clog the system, and fittings to connect multiple lines of drip tubing to a header line so that numerous beds can be watered at once.

Johnny's has drip irrigation kits, with everything needed for backyard or small market gardens. The components of the irrigation kits are also available individually for larger growers to set up more extensive systems.