Some garden vegetable plants and soil types require a consistent side-dressing of fertilizer throughout the growing season. To side-dress vegetable plants, you apply fertilizer to the soil on or around the sides of the plant. This practice is especially important in gardens with sandy soils that don't hold nutrients well, and during growth spurts when plants require lots of nutrients.
Side dressing takes little effort, and the payoff is a bountiful harvest. Keep these pointers in mind for side-dressing your vegetable garden:
Depending on plant spacing, side-dress either in a narrow furrow down a row or around each individual plant. In either case, spread granular fertilizer (which is easier to use than liquid fertilizer) at least 6 to 8 inches away from plant stems. Rake the fertilizer into the soil and then water.
Granular organic fertilizers, such as 5-5-5, are a good choice for side-dressing most root and fruiting crops. Use 1 to 2 tablespoons per plant, or 1 to 2 pounds for every 25 feet in a row.
For leafy green crops, fish emulsion is a quick-acting, highly soluble organic source of nitrogen that gives your greens a boost, especially if they're turning a pale green color. You can add micronutrients to this fertilizer by mixing it with seaweed. Add this liquid fertilizer to your watering can following the directions on the label. As you water, pour this solution around the bases of the plants and on the leaves.
Too much fertilizer can be more harmful than too little. Excess fertilizer accumulates in the soil in the form of salts and damages plant roots. So be sure that growing conditions enable plants to use the fertilizer that you apply. For example, don't add fertilizer during a dry spell if you can't irrigate your garden, because without adequate soil moisture, roots can't take up nutrients. And if cool weather causes your plants to grow slowly and need less fertilizer, go easy on the fertilizer until the temperature warms up or you'll be wasting it.
The kind of plants that you grow makes a difference in how often you side-dress. Plants that take a long time to mature (such as tomatoes and eggplants) and heavy feeders (like corn) generally benefit more from side-dressing than quick-maturing crops that fix their own nitrogen — such as lettuce, or legumes like peas and beans.
| Vegetable | When to Side-Dress |
|---|---|
| Beans, green | Not necessary |
| Beet greens | Two weeks after leaves appear |
| Beets | When tops are 4 to 5 inches high; go light on nitrogen, which encourages leaf growth |
| Broccoli | Three weeks after transplant; go light on nitrogen |
| Brussels sprouts | Three weeks after transplant; again when sprouts begin to appear |
| Cabbage | Four to six weeks after planting |
| Carrots | Three weeks after plants are well established and no longer seedlings |
| Cauliflower | Four to six weeks after planting |
| Celery | Three weeks after setting out; again six weeks later |
| Corn, sweet | Three weeks after planting; again when plants are 8 to10 inches high; again when tassels appear |
| Cucumbers | When they first begin to run (form vines and sprawl); again when blossoms set |
| Eggplant | Three weeks after planting |
| Kale | When plants are 6 to 8 inches tall |
| Lettuce, head | Three weeks after transplant; again when heads form |
| Lettuce, leaf | Three weeks after germination |
| Melons | When they begin to run; again a week after blossom set; again three weeks later |
| Onions | Three weeks after planting; again when tops are 6 to 8 inches tall; again when bulbs start to swell |
| Peas, English | Not necessary |
| Peppers, sweet and hot | Three weeks after transplant; again after first fruit set |
| Potatoes | When plants bloom |
| Pumpkin | When plants start to run; again at blossom set |
| Radishes | Not necessary |
| Spinach | When plants are about 3 to 4 inches tall |
| Squash, summer | When plants are about 6 inches tall; again when they bloom |
| Squash, winter | When plants start to run; again at blossom set |
| Swiss chard | Three weeks after germination |
| Tomatoes | Two to three weeks after transplant; again before first picking; again two weeks after first picking; go light on nitrogen |