Planting Tomatoes When the Soil is Too Cold

When planting seeds or transplants it is important for the backyard grower, community gardener or urban farmer to keep track of soil temperatures, as the soil is where the seed will germinate and where the roots are located.  It is not uncommon to have a large difference in soil temperature in relation to air temperature, especially early in the season.  A grower can get fooled into thinking the time is right for planting based on a warm sunny spring day when the soil temperatures are not actually at the point ready to plant.  I see tomatoes planted each year in April or early May that have been planted too early.

When planted before the soil warms up, phosphorus is not able to be taken up by the plant, even if enough phosphorus is present in the soil.  This manifests in a purple discoloration of the tomato leaves, especially the older leaves near the bottom of the plant.


The purple coloration is from anthocyanin, the same pigment that gives blueberries its color.  Phosphorus is a critical macro-nutrient that assists seedling growth and vigor.  These tomato plants are at risk of further disease or insect damage due to being stressed from nutrient deficiency.

To remedy this, you need to deliver phosphorus to the plant.  The best way would be to use a foliar feeding of a water soluble fertilizer containing phosphorus applied to the leaves, top and bottom.  This should be done early in the morning before the tomatoes stomata close. (the pores on the leaves).  Once the soil warms up the tomato will start to take up phosphorus if enough nutrient is present.  You may need to foliar feed until this occurs.

It is important for the backyard grower, community gardener and urban farmer to monitor soil temperatures to ensure that seeds and transplants go into the ground at the correct time to maximize production success and minimize potential problems.

Ohio State maintains a website with soil temperatures at all of the OARDC stations.  Click here for the link to check soil temperature in your part of Ohio.


Spring Gardening Classes at Bexley Community Gardens in May

There will be two classes held in partnership with City of Bexley Community Gardens to assist the backyard grower, community gardener and urban farmer.
Bring your friends and your questions to these informational garden walks to discuss how to improve soil health in your plot as well as talk strategies to combat the weeds that can drive you crazy.

Classes are free and open to the public.

Using Cover Crops for Weed Control in Spring

Cover Crops are a valuable tool in the toolbox of the backyard grower, community gardener and urban farmer.  I planted a mix of cover crop species last fall in my community garden plot to keep the soil alive over the winter, prevent erosion and increase soil organic matter.

Winter rye, forage radish, hairy vetch and crimson clover blend

This species mix, especially the winter rye component, can be challenging to manage in the spring depending on when the soil is worked.  The winter rye will die from mowing or crimping when it is going to seed and nearing maturity, but when tilled young, some of the grass will continue to grow.

The city tilled the garden in late March, some of the cover crops persisted and will continue to grow without further tillage or herbicide application.

The majority of my plot will be used for summer vegetables.  I do not want to leave the ground bare until that point as the cover crops will continue to grow in spaces and weeds will fill in the rest.  I would also lose organic matter and fertility from spring rains.

I rototilled over half of the plot to create a seed bed about 10 days after initial tillage.  This will kill most of the remaining over-wintered cover crops and created a seed bed for planting.

I followed up with a planting of Buckwheat.  Buckwheat is a versatile cover crop that tolerates poor soils, rapidly germinates, weed suppresses, attracts pollinators and when mowed, will rapidly break down prior to the next planted crop.



I will let the Buckwheat grow until mid-May.  Then I will mow the space which will kill both the cover crop and any annual weed that germinates within the Buckwheat planting.  It will also weaken any perennial weed that is growing.  I will let the residue decompose for a few days and then till and apply plasti-culture mulch in the pathways prior to summer vegetable planting.