Tomatoes need a long growing season, 6-12 hours of sun a day, and summer heat to set and ripen fruit. As a general rule, the larger the tomato, the more heat the plant needs. Beefsteak tomatoes need the most heat, and cherry tomatoes need the least.
Tomatoes perform better when you can mimic the conditions they evolved under. Tomatoes thrives best in environment with ample sun, high temperatures and humidity, fertile soil, and enough of water.
Grow Tomato in the Sunniest time of the year
Grow tomatoes in the sunniest, warmest part of your garden. Tomatoes can get by on 5-6 hours of sun and still produce fruit, but larger tomatoes need 8-12 hours of sun a day for best performance.
Tomatoes are summer vegetables that die at the first touch of frost. If you’re growing tomatoes, don’t make the mistake of setting them out before the last frost date for your area.
In temperate gardens in the northern and southern hemispheres, seeds are started indoors 6-8 weeks before the last frost date for the area, and planted outside after all danger of frost has passed.
Only in the warmest zone 9 gardens can you start tomatoes outside from seed and still get a crop, but even in this zone, you’ll have more and better fruit growing tomatoes from seedlings, not seeds.
If you set seedlings out too early and late frost threatens, cover them with cloches or newspaper cones to protect them until danger of frost is past.
Train Tomato Vertically
Tomatoes thrive in soils with a lot of organic matter and a deep root zone. The best way to grow tomatoes—especially in small gardens—is in a deep-dug or raised garden bed, and train them vertically.
If you have a lot of space and a deep, loose, loam with plenty of organic matter, they’ll do fine in widely-spaced rows.
Build the fertilizers into the soil when you plant.
Soil microorganisms break down organic fertilizers at varying rates. By mixing a quick-releasing organic soil amendment like alfalfa meal with a slow-releasing amendment like feather meal, you can provide for all your plants’ fertilizer needs at the beginning of the season.
Tomatoes need adequate nitrogen early in the season during their most active growth, but too much nitrogen creates excessive disease-prone foliage at the expense of fruit.
If you have access to good composted steer, dairy cow, sheep, or poultry manure, you can use a 2” (5cm) layer of composted cow or sheep manure, or a 1” (2.5cm) layer of composted poultry manure, in lieu of the alfalfa meal/feather meal combination. Sheep manure is particularly good for growing tomatoes because it provides phosphorous and potassium, as well as nitrogen.
Using Fresh Manure
Fresh manure can be used, but it needs to be tilled into the soil 3-4 weeks before you plan to plant, or it can burn your vegetables. Don’t just spread it on the surface, or you’ll lose most of the nitrogen.
If you use large amounts of good garden compost or the right amount of composted manure and have fertile garden soil, you might not need to add organic soil amendments for growing tomatoes.
If you’re starting a garden in a new place, or growing tomatoes in pots organically, you’ll get better results if you boost the soil with organic soil amendments for the first 2-3 years.
Using Kitchen Scraps
Once you’re recycling kitchen scraps and yard and garden waste through a compost bin and back into the garden, you can cut back on organic soil amendments or stop using them altogether, but for the first few years of a new garden, here’s what I use and recommend.
Alfalfa Meal for early-season nitrogen (8-12lbs/100 square feet, or 2lbs per 10 feet of row), as well as some phosphorous, potassium, and sulfur. Alfalfa meal is the best all-around fertilizer I’ve found for tomatoes and other summer vegetables.
Using Feather Meal
Feather Meal is ground-up chicken feathers, a byproduct of the poultry industry. It starts breaking down after about 8 weeks in the soil, and provides late-season nitrogen for heavy feeders like indeterminate (vining) tomatoes and squash. It also helps boost populations of beneficial fungi, including predatory fungi that attack root-knot nematodes. Use 1-1 ½ lbs/100 square feet (about 1 cup per 10 feet of row)
Using Kelp Meal
Kelp Meal for potassium, trace minerals, and growth factors that boost plant immunity. Use NO MORE than 1lb/100 square feet (a light dusting on each side of the rows)—kelp meal inhibits growth at high concentrations.
A hoe and some elbow grease—or a small tiller like a Mantis— to mix the compost, soil amendments, and topsoil together. Organic soil amendments must be in contact with soil microbes to be broken down by them, so mix them thoroughly into the soil.
Using Alfalfa Meal
The alfalfa meal provides for early-season growth, then the feather meal kicks in about mid-season, and supplies a steady, slow release of nitrogen to fuel late-season growth in indeterminate and late-season tomatoes. Kelp meal boosts resistance to diseases, which is important when growing tomatoes, especially if you’re growing heirloom tomatoes.
Of course, if you don’t feel like going to the trouble and expense of buying multiple organic soil amendments, you can always use a good, balanced organic fertilizer like Dr. Earth Organic Tomato, Vegetable, and Herb Fertilizer.
Pay attention to PH, phosphorous and potassium levels
When growing tomatoes, you also have to pay attention to phosphorous and potassium levels. Tomatoes need phosphorous for root, stem, and fruit formation, and potassium for flowering and resistance to diseases.
If you’ve had poor performance growing tomatoes in the past, the first thing to check is soil pH. Tomatoes grow best in a slightly acidic soil, pH 6.2-6.8. Alkaline soils have a pH of 7.0-7.8. High pH “locks up” phosphorous, potassium, iron, zinc, and many other minerals needed by plants.