Raise your tomato plants from seed whenever possible. If you bring plants in from the outdoors, you may introduce pests and diseases to your hydroponics system. Plant seeds in a nursery tray with a special growing material for hydroponics, instead of ordinary soil. Before using, soak the material with pH 4.5 water, aided by a pH test kit from a garden store. Plant the seed under the surface, and keep under plastic domes or other transparent material to trap moisture and encourage the seeds to sprout. As soon as the plants sprout, remove the covering and place the seedlings under a light source for at least 12 hours a day. Only use incandescent light bulbs as a last resort, as these produce more heat than other options.  See the section on hydroponics system setup to learn about grow light options. Take care not to let the light shine on the roots to avoid damaging them. If roots are protruding from the starter material before they are ready to transplant, you may need to soak additional starter material and use it to cover them. Wait until their roots start to protrude from the bottom of the nursery tray, and the first "true leaf" has grown, larger and different in appearance than the first one or two "seed leaves". This usually takes 10–14 days. When you move them into the hydroponics system, you may place them at 10 to 12 inch intervals in a layer of the same material, or transfer them to individual plastic "net pots" containing the same material. If using the ebb and flow system described in this article, the plants are placed on the tray. Other systems may call for the plants to be placed in a trough, along a slope, or wherever the water and nutrients can reach the roots. To begin with, try setting the pump to run for 30 minutes every 2.5 hours. Do not go more than 2.5 hours without running the pump. Keep an eye on the plants: you'll need to increase the watering frequency if they begin to wilt, and decrease it if the roots become slimy or soaked. Ideally, the material the plants are in should just barely dry out when the next watering cycle comes along. Even once the watering cycle is established, you may need to increase the watering frequency once the plants begin to bloom and fruit, since these processes require additional water. For ideal growing conditions, expose growing tomato plants to between 16 to 18 hours of light a day. Then turn off the lights and let them sit in total darkness for about 8 hours. The plants will still grow if you are relying on sunlight, but will likely grow more slowly. Some tomato plants are "determinate," meaning they grow to a specific size, then stop. Others continue to grow indefinitely, and may need gently tying to a stake in order to grow upright. Prune them by breaking off stems with your hands rather than cutting them off. Keep in mind that even though determinate tomatoes will grow without staking, there is a risk of lower yields if you do not stake the plants upright. When the plants set fruit, they may droop and come into contact with the growing medium. When the tomato plants bloom, since there are no insects in your hydroponics environment to pollinate them, you will need to do it yourself. Wait until the petals bend back to expose the round pistil and the pollen-covered stamens, or long, thin sticks at the flower center. Touch a soft paintbrush to each of the pollen-covered stamens, then touch the rounded end of the pistil. Repeat daily.
ازرع بذور الطماطم في مادة خاصة. اترك البذور أسفل مصدر صناعي للضوء بعد أن تتفتح. حرك الشتلات إلى نظام الزراعة في الماء. جهز مؤقت مضخة الماء. ركّب الأضواء الصناعية (إن كنت الأمر متاحًا). شذب وأدعم نباتات الطماطم الطويلة. لقّح زهور نباتات الطماطم.