Spring Planting

The days are ticking down toward spring planting. This is exciting! I would like to outline the steps our farm undergoes in late February to get ready for spring planting. We start planting seeds indoors on the week of March 8th. This is based on our zip codes last frost date. We generally have our last frost around May 3. We don't set out tender plants till May 10 (and then look at the 10 day forecast just to be sure). Remember that frosts can sneak up on you on clear sky nights without weather forecast warning. I have even seen light frost with 10 degrees safety margin in the forecast.

If you have not yet obtained your seeds, now is the time! Following are the seed companies we have used over the past several years:

• Johnny's Select Seeds
• Baker Creek Seeds
• Harris Seeds

It is also time to setup your start trays in which you will start your transplants. We use recycled 4x8 foot drop ceiling light fixtures (4 bulbs), placed on 4x4 inch blocks which lifts the light fixtures just above the trays. The light should be as close to the plant as possible to give the maximum light exposure. If your plants are tall and leggy, they do not have enough light.

We have used grow heating mats in the past. I found that if I cover the light fixture with a blanket, the heat of the light fixture warms the under contents adequately as measured with a soil probe thermometer. Be careful if you try this. Make sure you don't have too much heat creating a fire danger. I set up several test configurations on my seed starting setup, and measured the temperatures obtained. The variables: no light or added heat, light on, heating pad and blanket cover. All of these measures were taken on the same light unit, at a room temperature of 60-70 degrees. In my testing, I found:

1. Soil at room temp, no light or heat added    60 deg
2. Heating pad on only                                    80 deg
3. Heating pad on covered with a blanket       86 deg
4. Light on only                                               62 deg
5. Light on covered with a blanket                  82 deg
6. Light on + heating pad on                           84 deg
7. Light on + heating pad on + blanket            96 deg

When we plant, we want to remember the goal is a progressive harvest, and this means not planting all of the cabbage for a single harvest, but progressive plantings. Elliot Coleman, in the book Four Seasons Harvest, suggests this schedule on page 88:

• Beans - every 2 weeks
• Beets - every 2 weeks
• Carrots - every 2 weeks
• Celery - twice: early spring, and 3 months before fall frost
• Corn - every 2 - 3 weeks (some varieties vary in length so keep this in mind)
• Cucumbers - two or three plantings: at month intervals
• Lettuce and greens - every week or two, extending the entire season
• Peas - twice: early spring and midsummer
• Radishes - every week
• Spinach - every week during spring and late summer
• Summer squash - two or three plantings at month intervals

We have created charts for planting dates based on the projected last frost date in spring. I will describe how we have constructed our chart, and then you can modify the specific dates based on your last frost date. I will only list the first planting of a variety here, though remember the suggested schedule above related to progressive plantings.

In the chronology below, the word "start" means seeding a transplant tray to start seedlings in side under lights. "Transplant to soil" means taking some of these seedlings and transplanting these into their final location in the garden. "Plant in soil" means we seed directly to the garden. We do not notate seedling transplants to larger pots indoors, but in several cases, this is needed. We have eggplant inside a long time before we set it out, as an example. We largest pot we use inside is 1 gallon.

Eight weeks before last frost date (Mar 8), we start the cold crops: cabbage, cauliflower, kale and lettuce.

Seven weeks before last frost date (Mar 15), we start egg plant and broccoli. Eggplant is a slow growing, warm loving plant, but it needs a long growing time to get it to harvest, so we start some really early. Onions can be planted in soil.

Six weeks before last frost date (Mar 22), we plant in soil: arugula, spinach and peas. 

Five weeks before last frost date (Mar 29), we start endive and turnip. We transplant to soil: cabbage, cauliflower. Plant in soil: radishes. 

Four weeks before last frost date (Apr 5), we start peppers and tomatoes. We plant in soil: beets and potatoes.

Three weeks before last frost date (Apr 12), we transplant to the soil: broccoli and lettuce.

Two weeks before last frost date (Apr 19), we start beans. We plant in soil carrots and chard.

One week before last frost date (Apr 26), we start cucumbers, summer squash and melons.

Week of last frost date (May 3), we start okra, another warm loving plant that we will transplant to soil in 4 weeks.

One week post frost date (May 10), we start pumpkins. We transplant to soil the beans. We plant corn and a successive planting of beans into soil.

Two weeks post frost date (May 17), we transplant to soil cucumbers, summer squash and melons.

Three weeks post frost date (May 24), we transplant to soil peppers and tomatoes.

Four weeks post frost date (May 31), we transplant to soil the okra and pumpkins.

While the seedlings or transplants are being established in soil, more diligent effort with weeding will be required. As soon as the plants are large enough to withstand some side dressing of mulch, apply this and add to it as you are able. This will do wonders for controlling your weeks, and lessening your hoeing work.


Soil

I wanted to have you think about the soil you use for your starter trays. We have used commercial starting mixes with good results in the past. Some references talk about using pasteurized soil, where harmful bacteria have been killed, but not so hot that the organic material is turned to charcoal. Be aware that if you use untreated garden soil, you may have more problems with damping off when used in a greenhouse or starter house application. I don't have a lot of experience pro or con, but pass on the word of caution from others.


Hardening off

When plants are started inside or in a greenhouse, the plants are tender. If placed directly outside, they may be burned and die. In our experience there are two key issues: light intensity and stem strength. New plants that have been inside have been shielded from the full intensity of the sun, and if the plant is directly transplanted outside with no hardening, the plant may be set back by leaf burn. Stem strength is also an issue, as indoors the plants are not subjected to wind stress, and stem strength develops based on need. I have sometimes set an oscillating fan to blow across the plant trays. I set plants out in the middle of the spring day that is sunny and warm for a limited amount of time. This time I increase an hour a day leading up to the date we transplant to soil.


Transplanting

When you are ready to transplant to soil, you will want to mark out the transplant bed in advance. We use a transplant trowel which is perfectly shaped to open the soil to receive the new plant. Take care to adjust the roots and rootlets to prevent root ball. Gently firm the soil around the plant, as this will improve capillary action to bring water to the roots. Generally you will want to plant the seedling at the same soil depth as they were grown prior. An exception is tomatoes, which will root out of a buried stem. There may be benefit to transplanting to the base of the first leaves.


Resources

• First and last frost dates for your zip code (web)
• Water Your Seedlings with Chamomile Tea to Prevent Damping Off (web)
• Safe Seed Resource List (web)